[Neutered10mm]

Long story short, completely destroyed my G27 when I had a case head/web blowout at the 6'oclock position. This was round #10 in a 15 round magazine and the remaining 5 rounds had varying degrees of setback caused by the explosion. Happy to report I'm typing this with all fingers intact, although very sore! :what:

Not sure exactly how this happened as my crimp has been sufficient for my prior 500+ rounds without incident. When setting up the press, I initially checked OAL to be at or within .005 of 1.130 trying not to exceed 1.135 due to how unsupported 1.140 looked and how it goes against everything I have seen printed in manuals. After I got the proper setback, I setup the crimp die with unprimed brass and kept turning up the crimp until it took an excessive amount of hits with it in the breakdown hammer to get the bullet to unseat.

Is there another way to test the crimp? I'm fairly certain this occurred due to an oversight on my part when running my son through the process to show him exactly what I have been tinkering with (he's fascinated with the different cases and bullets). I let him run his own dummy rounds and may have forgot to reset the dies. Dumb I know ... I don't need a lecture, I'm fairly certain this is one event I will never forget and most definitely will learn from.

The remaining 40 rounds will be broken down and assessed and the crimp die will be recalibrated, but I was wondering other than testing crimp with the breakdown hammer on an unprimed case, how do YOU check for crimp strength???

[MtnCreek]

IMHO, you may have a neck tension issue. This is a .40, correct? Crimp should not be required to hold the bullet in place. Also, I wouldn't judge my neck tension by it's ability to hold the bullet in place during a KB.

Edit: I push the bullet against my bench. If it measures the same after, it's good to go.

[Mike 27]

Your crimp should only take the bell out. A heavy crimp is not required on semi auto pistols. How many times have the cases been loaded? What components, and charge did you run? Pull down the remaining and check the powder weight. Glocks have the un-supported chanmber at the feed ramp, and it sounds like that is what blew out. Glad to hear you have all of your digits, and ok....I have to think this was not a crimp issue unless you really overcrimped. The mouth should be .423 per the SAAMI drawing.

[Neutered10mm]

Yes, I'm reloading .40

Yes, I also had checked that (measure, press on bench, remeasure) after initial setup and did so before putting in the hammer for breakdown. The more and more I mull this over, it comes back to me forgetting to recalibrate the die after showing my son how the press operates (walked him through an entire setup routine).

I'm just curious if anyone makes a special tool specifically for this purpose. Something I can put in my QA/QC routine. As it is WAS, I did initial setup of each die station, measured the powder charge on the first 5 rounds and then every 5th round. Each round of each 50 produced was then checked for OAL to ensure they were within spec. As it IS now, I'm going to add a nose press of EVERY round and recheck OAL before they are boxed for the range bag, NOT just on initial die setup.

[MrCountyCop]

Glad you still have all your digits!!

[Walkalong]

Yep, as posted by MtnCreek, neck tension holds the bullet in .40. Crimp is just to remove the bell or a hair more so it will fit the chamber.

Try the press a round against a hard surface to see if it moves trick. If it does, you do not have enough neck tension. If so, your sizer is to big, or your expander is too big, or both. Load a couple of rounds without using the expander and see if you have adequate neck tension. If you do, the expander is too big, or you are way over expanding. You can turn the expander down a couple of thousandths and try it again. RP brass is also notorious for being thin and having inadequate neck tension when thicker brass does fine.

No amount of crimp can make up for poor neck tension in .40. What bullet and charge?

[243winxb]

Plated Bullets?

[Neutered10mm]

@Mike 27 ... brass was once fired from a police range pickup. Brass was then tumbled in a Thumblers Tumbler with SS media, 1 gallon of water, Lemishine & Dawn. After drying, bases were lubed, run through Lee De-bulge kit and then through each station of my setup. Station 1 = deprime/resize, Station 2 = prime/bell, Station 3 = powder, Station 4 = powder cop, Station 5 = seat/crimp. The reloader is a Hornady LNL AP and the dies are Hornady.

[Neutered10mm]

Bullets are Ranier 165gr plated double struck (hollow point only because they had a great deal of $104/1,000 vs. $122/1,000 otherwise I would opt for flat nose). Brass is once fired police range brass, 85+% federal, some Winchester. Powder is Hodg TightGroup @ 4.7-4.9gr & primers are CCI #500's.

[Neutered10mm]

I'll get pictures up later ... pressure involved is thoroughly impressive! Thanks for the "glad you have your digits" comments! Was my wife's first time at the range in 10+ years as I'm trying to get her into the hobby as well so we both can enjoy it ... needless to say I'm extremely greatful it went off in my hands and not hers!!!

[chaplain 31]

I don't consider myself an expert on this, but I'm having a hard time understanding how crimp could cause this, unless it was so light and the case tension was not right that it allowed the bullet to be pushed back into the case during chambering. I've shoot thousands of rounds of "lightly" crimped 40 with no problems of any kinds. Is there a possibility something else caused this.

[243winxb]

Thats the problem > plated bullets. Or double charge of powder. Hodgdon website- This data is intended for use in firearms with barrels that fully support the cartridge in the chamber. Use of this data in firearms that do not fully support the cartridge may result in bulged cases, ruptured cases, case-head separation or other condition that may result in damage to the firearm and/or result in injury or death of the shooter and/or bystanders.

[Neutered10mm]

going down to the reloading room right now to bust out the calipers ... the remaining 5 rounds in the mag have their bullets setback quite a bit. This leads to a massive pressure increase from what I have read on the subject. Doesn't help that the .40 is already a "hot" load right out of the box with pressures routinely in the 33,000 psi range. According to multiple sources "Hirtenberg Ammunition Company of Austria (at the request of GLOCK, Inc.) determined that, with a .40 caliber cartridge, pushing the bullet back into the case 1/10 of an inch doubled the chamber pressure." That being said, I'd care to guess just my eyeball, at least 2 of the remaining 5 bullets in that mag exceed this (my guess is explosion rocked them hard enough to cause setback). The entire magazine nearly blewout (dropped an inch) and the polymer casing around the metal inner shell of the magazine fractured in MANY places. The frame cracked in 3 places, etc ... will get pictures up soon.

[Neutered10mm]

@243winxb ... how would bullet type cause this? Please elaborate.

[Neutered10mm]

I'm suspecting bullet setback at this point based on the remaining 5 rounds ... I don't suspect the components ... hell, if anything, I'm impressed at how well everything held together with the case.

[biogenic]

I don't consider myself an expert on this, but I'm having a hard time understanding how crimp could cause this, unless it was so light and the case tension was not right that it allowed the bullet to be pushed back into the case during chambering. I've shoot thousands of rounds of "lightly" crimped 40 with no problems of any kinds. Is there a possibility something else caused this.

I agree. Sounds like too much powder entered the casing or a bad piece of brass. Did you visually inspect all the brass?

[Mike 27]

I saw somewhere on a spec sheet that the Lee bulge buster was not to be used on 40/10mm because of the unsupported chamber. I would have to dig for it and have to go to work so can't right now. Maybe one of the smart guys knows. I almost bought it for my 10mm G20 until I read this. Maybe it has something to do with it especially at the location on the case failure. Taking the glock bulge out may be your issue. Check their website for it, but I am almost positive it says not to use it for the .40 or the Glock.

[Neutered10mm]

I don't have a case feeder, so I manually feed each round, prior to feeding, I inspect the brass. This is a 2nd check as I do a visual inspection prior to de-bulging. Fairly certain the brass isn't to blame and I my press routine is this: press down, hold, inspect powder cop, inspect powder measure (ensure full travel), inspect visual indicator of the primer rod ... leading to me to believe my powder charge was in spec as well.

[918v]

You keep saying the ammo remaining in the mag exhibited setback. But it had not yet been chambered. So how did the setback occur?

Not sure exactly how this happened as my crimp has been sufficient for my prior 500+ rounds without incident. When setting up the press, I initially checked OAL to be at or within .005 of 1.130 trying not to exceed 1.135 due to how unsupported 1.140 looked and how it goes against everything I have seen printed in manuals. After I got the proper setback, I setup the crimp die with unprimed brass and kept turning up the crimp until it took an excessive amount of hits with it in the breakdown hammer to get the bullet to unseat.

This is not the way to adjust a crimp die. What you did there was dig the case mouth into the bullet, but at the same time ruined case tension on the bullet. It's like this: if you try to force brass into a non-existent crimp groove, the case walls below the case mouth will collapse sway from the bullet. What you end up with is a round being held together entirely by the crimp, and not by brass tension.

I have seen people write they applied so much crimp, but they can spin the bullet in the case with their fingers. They wrote they continued to add crimp but it didn't help. That is exactly what you did. You belled too much and crimped too much thinking the crimp is what holds the bullet in place.

To properly adjust the crimp die you screw it down to remove the visible bell from the case mouth and no more.

[Striker Fired]

If you were crimping too tight, it is possible that the mouth of the case that blew slipped into the throat.If it does that the bullet gets wedged and the pressure skyrockets. Take some pics of the remaining rounds and let us see your crimp and how the rounds looks.

[Neutered10mm]

918v ... this is NOT the case ... pictures will show no excessive crimp. In the quoted text, I forgot to mention that if at any time I noticed the bullets were creased by the crimp, I backed off. My bullets are being held in by neck tension and perhaps I'm misusing the term "crimp". My crimp isn't reverse belling and literally grasping the bullet ... I made certain this wasn't the case. Again, the pictures of the remaining 5 rounds will tell the story I'm sure.

As for how the remaining 5 got setback ... I'm sure 50,000+ psi being forced upon the bullet nose (hollow point remember) and then rocking them forward would have such an effect. Yes they weren't chambered, but they were certainly placed under an EXTREME amount of pressure from the prior round exploding just above them. Keep in mind, the blowout was at the 6 o'clock position, shooting the pressure down the feed ramp and directly at the rounds below.

[biogenic]

I don't have a case feeder, so I manually feed each round, prior to feeding, I inspect the brass. This is a 2nd check as I do a visual inspection prior to de-bulging. Fairly certain the brass isn't to blame and I my press routine is this: press down, hold, inspect powder cop, inspect powder measure (ensure full travel), inspect visual indicator of the primer rod ... leading to me to believe my powder charge was in spec as well.

You mention leading.... How do you get leading when you use fmj or plated bullets ?
Glock specifically warns against lead bullets. Did you use lead ? If you did, the obstruction caused by leading could result in blowing up your gun,especially Glocks

[PO2Hammer]

The best way IMO to check for set back is to make up several dummy rounds (no primer, no powder) with the same components and die setting as your load.

Load them into the magazine and cycle them in and out of the gun by pulling the slide back and letting it fly forward.
My plated .40 loads will set back less than .005" after three times through the gun.

Bullet tension is the key to preventing set back. With plated bullets in .40 I use the Lee universal expander die (http://www.midwayusa.com/product/140461/lee-universal-case-expanding-die), it's a conical flaring tool that puts just a little flare (.003"-.005") on the case mouth without opening up the 'neck' area of the case. That lets the bullet do all the expanding and increases the case's grip on the bullet.

Then just use a taper crimp die to remove any trace of the flare.

[243winxb]

@243winxb ... how would bullet type cause this? Please elaborate. The soft lead bullet core can be swaged smaller by taper crimping to much. The cartridge brass can spring back, but a lead bullet will not. This leaves little neck tension to hold the bullet. If a jacketed bullet is swaged dowm more than .005" the lead core becomes loose also. We, at Rainier Ballistics, recommend using lead bullet load data when loading our bullets. There is no need for adjustment when using lead bullet load data. Our bullets are jacketed using an electroplating process and are softer than traditionally jacketed bullets; hence the recommendation to use lead bullet load data. If you only have access to traditionally jacketed load data, we recommend a starting powder charge directly between the listed minimum and maximum load. A roll or taper crimp may be used with our bullets; do not over crimp. As in most KABOOMs, we may never know the real cause.

[Neutered10mm]

biogenic ... leading and leading ... don't you just love the English language :D

In context, I was led to believe ... leading me to believe. Also, if you have any press experience or work in the graphic design field, leading is also the space between lines of text because movable type from the 16th century up until digital presses were invented used lines of lead to gap the font "slugs" ;)

[bbuddtec]

yep i was going to go w/ oal...

[918v]

918v ... this is NOT the case ... pictures will show no excessive crimp. In the quoted text, I forgot to mention that if at any time I noticed the bullets were creased by the crimp, I backed off. My bullets are being held in by neck tension and perhaps I'm misusing the term "crimp". My crimp isn't reverse belling and literally grasping the bullet ... I made certain this wasn't the case. Again, the pictures of the remaining 5 rounds will tell the story I'm sure.



If you didn't overcrimp, then you may have belled too much. If you did not bell too much, then this:

A while back I did a crimp test. At the same time another person in another part of the country did a crimp test. He claimed he was able to stop bullet setback by adding crimp. The proof was in the drycycling of the pistol. My test showed no such improvement in bullet retention.

I used a .450" plated bullet to prove my point. The undersized bullet set back no matter what the crim was set to. I even cranked the die down so much the round became bottlenecked. The crimp did not hold the bullet. My .452" bullets did not move in the case with a light amount of crimp, even after 10 chamberings.

It could be you have a crappy batch of undersized bullets and that is why you are seeing setback. No amount of crimp will compensate for a lack of bullet diameter.

[bds]

First, welcome to THR!

Second, glad you are OK and nobody got hurt!

Third, thanks for posting/sharing your experience as I am sure it may help countless others prevent a KB.


Now, to do the "root cause analysis" of the KB ... and we are ruling out a double charge, right? Then what's left to cause a KB are the combination of the following:

- Over charge of powder (Weigh several powder charges to verify. As others posted, Rainier suggest you use lead load data. There is no current published lead load data from Hodgdon for Titegroup)

- Bullet seated too deep (Load several more rounds with the same bullet and measure the OALs. For 165 gr JHP Rainier bullet, OAL should be around 1.125")

- Too much crimp that may have cut into the plating caused plating separation (For .400" sized Rainier plated bullets, no more than .420" taper crimp should be used - any more and case neck edge may cut into the plating. Measure the taper crimp of several loaded rounds and pull the bullets to see if plating was cut into)

- Weakened brass case (This would be harder to determine as once-fired brass can have different conditions of brass depending on the pistol/barrel/powder/charge that was used on the initial firing)


To prevent another KB, I would carefully retrace every step of your reloading procedure to identify where the problem area(s) were and add quality control (QC) steps as necessary.

[Bovice]

A little too much Titegroup and some setback will blow up your gun in short order. What most people don't realize is that 9mm operates at nearly the same pressure as the .40, so it being "high pressure" and in a class of it's own in this respect is wrong. It's possible that you had some setback, but we'll never know for sure. The best plan to proceed is a couple of things.

A blowout at the 6 o'clock sounds like you had a bad piece of brass. Over-bulged cases which are resized will have a sharp ridge near the case head where the slack from the bulge has been taken up. If you see this, disassemble the round and throw the brass away. A good round will have the coke bottle/wasp appearance. Anything else should be suspect.

A safer way to apply your taper crimp is to do it in another step, separate from seating. Seating dies can easily crimp too much and ruin your neck tension.

[Neutered10mm]

I just took some video of my breaking down the rounds, taking some measurements, making a new dummy round and breakdown, etc. Here are some interesting findings ... the rounds in question had a crimp line in the bullet, but not sever enough to break through the plating ... think how you get sock lines in your skin if you are dehydrated, or pillow crease lines on your cheek ... nothing excessive, but then again, I'm hear for advice, I'll post pictures and assume nothing.

On my built dummy, no line and retained damn well (took 7-8 fairly good blows). The "suspect 5" were broken down in 2-3 blows (only took down 3 of them). I'm downloading the pics and vids now ... will post in a few minutes.

[rcmodel]

IMO: I would not use a very fast powder like Titegroup in .40 S&W on a bet.

You are skating on thin ice at near max loads, even under the best of circumstances.
Add in bullet setback, or a weak case and you are gonna blow up.

I'd switch to a slower more forgiving powder that fills the case to the base of the bullet.
It is not as critical, even if the load becomes a compressed charge due to set-back.

rc

[jibjab]

Try the press a round against a hard surface to see if it moves trick. If it does, you do not have enough neck tension.
Is there a more precise way to test case tension ? or are we stuck with "that seems about right" I was thinking of a gauge to measure the amount of force needed to move the bullet, and is there a standard this measurement could be compared to ?

[Neutered10mm]

I will more than likely take that advice! I was looking at the Hodgdon for my load data and the "hottest" load I have logged is a 4.9 ... 4.7 starting, 5.1 max ... figured I was safe with a 4.9 personal max. My first 150 rounds were loaded to 4.7 and they ran cycled fine, were snappy, but not excessive. The last 400+ rounds were 4.8-4.9 ... it's entirely possible a case may have been charged to 5.0-5.1 as it wouldn't have raised the Powder Cop a describable amount.

Looks like I will have to attach these in batches since there is a 4 attachment limit per post :banghead:

http://www.thehighroad.org/attachment.php?attachmentid=160014&stc=1&d=1330362691

http://www.thehighroad.org/attachment.php?attachmentid=160015&stc=1&d=1330362691

http://www.thehighroad.org/attachment.php?attachmentid=160016&stc=1&d=1330362691

[Neutered10mm]

My hands:

Left hand between the thumb main knucle and hand joint ... that meaty pad ... got the smack of it's life with the mag release. The pressure was great enough to explode the mag release mechanism in half, sending the other half (right side) out of the gun and the left side (mag release button) into my thumb.

http://www.thehighroad.org/attachment.php?attachmentid=160018&stc=1&d=1330362946

Right hand ... trigger finger was abused by the Glock's right trigger side as it exploded outward.

http://www.thehighroad.org/attachment.php?attachmentid=160019&stc=1&d=1330362946

[Neutered10mm]

Gun body is pretty FUBAR!

http://www.thehighroad.org/attachment.php?attachmentid=160020&stc=1&d=1330363270


http://www.thehighroad.org/attachment.php?attachmentid=160021&stc=1&d=1330363270

[Neutered10mm]

hmmm, this isn't going to come out easily was my first second and third thoughts ... I was right ... took a little more beating with a hammer that I was comfortable with.

http://www.thehighroad.org/attachment.php?attachmentid=160024&stc=1&d=1330363600

My lucky horseshoe?

http://www.thehighroad.org/attachment.php?attachmentid=160025&stc=1&d=1330363600

http://www.thehighroad.org/attachment.php?attachmentid=160026&stc=1&d=1330363685

[Neutered10mm]

Extremely grateful I'm typing this with all 10 digits!

http://www.thehighroad.org/attachment.php?attachmentid=160027&stc=1&d=1330363835


http://www.thehighroad.org/attachment.php?attachmentid=160028&stc=1&d=1330363835


http://www.thehighroad.org/attachment.php?attachmentid=160029&stc=1&d=1330363835

[MtnCreek]

You can rule out bad brass or anything else that wont raise pressure dramatically. Judging by the head of the fired brass (exploded brass), I'd say you were in excess of modern rifle pressure.

[Mike 27]

Ok I found the Lee bulge buster disclaimer, and this sounds like it could have been the issue. After seeing your pics I am glad to hear you are ok.

From the Lee Website:

"Glock Cases: We do not recommend "fixing" cases fired in pistols with unsupported chambers, because there is no way to make them safe once they have bulged. The case wall is thinned where it bulges, and resizing the outside of the case back down to the correct diameter does not restore the case back to its original thickness. If this case is fired in a pistol with an unsupported chamber again, and this thinned section of brass happens to line up with the unsupported part of the chamber, there is a high probability that the case will rupture."

Just some food for thought,

Mike

[Neutered10mm]

As I said before, my QC process involved measuring OAL and shooting for 1.130 +/- .005 as acceptable. I would setup the press, powder measure the first 5 rounds till they are consistently throwing my goal, then checking every 5th round after that. Once I get 50 produced, I'd check the OAL again before boxing them up. I loaded 2 G22 mags (15 rounds) and 2 G27 mags with the Pearce Extended Baseplates (+1), allowing me to load the entire box in 4 mags. After the KB, I unloaded the remaining 35 rounds (remember, this happened on round 10, 5 remaining in the exploded mag) and put them in the same box as the remaining 5. Here is a picture of one of the suspect rounds (haven't pushed on the bullet yet to test, will do so after posting this) measured.

http://www.thehighroad.org/attachment.php?attachmentid=160031&stc=1&d=1330364308

Compared to the of the 5 survivors! :what: :what: :what:

http://www.thehighroad.org/attachment.php?attachmentid=160030&stc=1&d=1330364308

[Neutered10mm]

@ Mike 27 ... same thing is printed on an insert that came with it ... have heard from numerous reloaders on numerous forums that reload .40 without incident and this disclaimer is merely a warning to CYA in case I were dumb enough to sue over something like this. I accept this is fully my fault, I'm now just trying to find out why.

[Mike 27]

I considered picking one of these up for my Glock, and saw it....Not sharp shooting you, thought it might be helpful....


Mike

[Neutered10mm]

Thanks, I appreciate you taking the time to post what you had found on Lee's site. Lee includes the same disclaimer in the kit and even Hornady advises against reloading already shot .40 ... perhaps this will lead me to either increase or decrease my replacement caliber. Currently I'm considering a G23 with a 9mm conversion barrel and not reloading since 9mm is affordable ... still on the fence as I'm admittedly "gun shy" with anything coming off my loader from here on out until I can nail down the cause and address it.

[918v]

"Glock Cases: We do not recommend "fixing" cases fired in pistols with unsupported chambers, because there is no way to make them safe once they have bulged. The case wall is thinned where it bulges, and resizing the outside of the case back down to the correct diameter does not restore the case back to its original thickness. If this case is fired in a pistol with an unsupported chamber again, and this thinned section of brass happens to line up with the unsupported part of the chamber, there is a high probability that the case will rupture."


There is a difference between "bulge" and proper expansion. A "bulge" is when the brass starts to flow down the feed ramp. A properly expanded case, such as what you see 99.9% of the time, is not damaged and can be reloaded a bunch of times. The problem is people confuse normal Glock case expansion with a bulge.

This is a bulge:

http://www.wingman26.com/images/shooting/glock-brass.jpg

[ny32182]

It might help if you post a close up picture of the crimp on a loaded round, and also a pic of one of the pulled bullets... there should not really be a ring in the bullet.

However, my money would be on "none of the above"... as mentioned, you generated a massive overpressure somehow. Not a little overpressure, but a big, massive one. I don't think a little bullet setback could make the case look like that. I'm guessing that somehow, some way, too much powder ended up in that one.

[Certaindeaf]

If a 9 gets set back 1/10" from minimum, the pressure is doubled. I think.
Neck tension is good.

[918v]

That all depends on the powder and the bullet and OAL. If that were always the case nobody would have any fingers left.

[Striker Fired]

I'd say it is a safe bet that the cause was loaded at/near max charge with a fast ,unforgiving powder & setback issues created way-overmax pressures in an unsuported chamber that shouldn't be loaded to max to begin with.

This is one of the main reasons I am not interested in any fast powders, I always use slower powders that fill the case up enough , and won't be as tempermental if the bullet gets pushed in a bit.

It's just one of those life learning lessons. Glad you or your other half didn't get hurt. Now ,time to save up for a replacement.

[Neutered10mm]

Well, just came up from the reloading area ... I pulled 2 of the remaining 35 suspect rounds, put their nose on the bench, put my thumb on the base and pressed pretty good (wish I had a way to measure as this was the point of the thread) ... the bullet recessed from 1.1315 to 1.084. Did another 1.132 down to 1.114 ... didn't bother checking further ... this batch will need to be broken down and redone. How much pressure was applied? I have no idea ... I'm 5'10", 210 lbs. with strong shoulders ... I've done plenty of automotive work with a torque wrench and my educated guess ... about 50 ft/lbs. of downward torque on the bullet.

I'd imagine it could be done to ANY bullet, but a properly tensioned/retained bullet would buckle/wrinkle the case first???

[Neutered10mm]

Oddly enough, I just sold a set of tires/rims to a guy the day before for ... drum roll ... $550 :D

[918v]

Pull the bullets and measure their diameter.

[MtnCreek]

I'd imagine it could be done to ANY bullet, but a properly tensioned/retained bullet would buckle/wrinkle the case first???

Unless it's roll crimped or a heavy taper crimp into a canalure, the bullet will setback with enough force.

I'm betting on too much tight-group. Is your press still setup just as it was when you loaded these cartridges? If so, I suggest going through every station. Size & Measure. Bell & Measure. Charge & Measure……

[MtnCreek]

I'd say it is a safe bet that the cause was loaded at/near max charge with a fast ,unforgiving powder & setback issues created way-overmax pressures in an unsuported chamber that shouldn't be loaded to max to begin with.

This is one of the main reasons I am not interested in any fast powders, I always use slower powders that fill the case up enough , and won't be as tempermental if the bullet gets pushed in a bit.

It's just one of those life learning lessons. Glad you or your other half didn't get hurt. Now ,time to save up for a replacement.

Looks like a Gen 4; I think they are fully supported now, I think...

[GLOOB]

All plated bullets aren't the same. Rainiers shoot more like cast bullets than Berrys. So when you hear other people recommending jacketed data for Berrys, you can't transfer that to all plated bullets. Rainiers specifically recommends using cast lead data for their bullets. Berrys specifically recommends low to mid level jacketed data for their bullets.

My own personal experience with trying to substitute 155 grain Rainer's for 155 gr Berry's without changing load data was I ended up with loads that were too hot for my G27. So hot, they sometimes failed to extract, at all. To be fair, the Rainers were a smidge longer, decreasing internal case volume, but not by much.

Side note: after playing with lots of different loads in a few different 40sw guns, I'm pretty convinced that the G27 is borderline for max loadings. A heavier spring can fix that, but it also increases the propensity for limp-wrist malfunctions. I am currently leaving my 9mm conversion barrel in my G27, by default. I shoot most of my 40 through my FNX, these days.

[918v]

I did a QuickLoad check of your combo. Assuming you were using a 180 grain bullet, reducing the OAL from 1.135" to 1.080" raised the pressures by 25000 PSI, theoretically.

[243winxb]

wish I had a way to measure and this my point of this thread) For the 223, i have taken a bath room scale. A piece of wood to form leverage to push the seated bullet into the empty case. Should take 35 to 45 lbs. Seating of the bullet will expand the neck about .002" on seating. I have no idea of what 40 S&W neck tension should be?? Possibly run a test with factory ammo (not sure this is safe??) or a jacketed bullet dummy ?? Great photos.

[Neutered10mm]

I was thinking of a similar approach (bathroom scale) ... need to get ahold of some Hornady 165gr. Critical Defense first ... my carry load is 180gr Hyrdrashock. I will definitely keep this thread updated with my findings. I did manage to work up a dummy round on the current press setup and it's outside diameter after seat/crimp was .422" and it took 7-8 blows to remove it ... bullet uncreased ... forgot to pressure check setback, but can do so after work today.

Thanks A LOT guys for all the input ... keep in coming!

[Certaindeaf]

Looks like a Gen 4; I think they are fully supported now, I think...
To me, it looks to be about half supported.

http://www.wingman26.com/images/shooting/glock-brass.jpg

[rg1]

What's the possibility that the pistol fired out of battery without the case fully chambered. The blown up case in the barrel looks like it was fully chambered but the damaged case looks like it wasn't fully chambered. Any Glock armorer experts with any thoughts on "firing out of battery"?

[Certaindeaf]

.My own personal experience with trying to substitute 155 grain Rainer's for 155 gr Berry's without changing load data was I ended up with loads that were too hot for my G27. So hot, they sometimes failed to extract, at all..
Were you ripping rims off? Sounds odd.

[dwhite]

Would a slower powder, say Unique, have the same increase in pressure with the same amount of setback as compared to the Titegroup load?

Titegroup in .40 is just scary. Now I've used Clays before but only in bunny fart loads just enough to eject the spent case. No way I'd start pushing max with either of these.

All the Best,
D. White

[MtnCreek]

Out of battery...

Look at post 36, photos 2 and 3. The case head has had some serious pressure to mare the casehead like that. Also, post 37, photo 3. The case looks like it was seated in the chamber to proper depth; it just extruded out because of way excess pressure. If I every dbl charge a case, I'll probably question if it was fired out of battery...:)

[gunnysmith]

Reference this thread concerning the difficulties of unsuppoted chambers:
Photos on Page 2

http://www.thehighroad.org/showthread.php?t=645850&p=7992259#post7992259

[Certaindeaf]

.If I every dbl charge a case, I'll probably question if it was fired out of battery..
Note depth measurements and post #55.

[GLOOB]

Were you ripping rims off? Sounds odd.
No. The extractor jumped the rims and left the brass in the chamber, leading the gun to doublefeed. (Also, the recoil was brutal, and I couldn't keep the rounds on a pie plate at 25 feet!) The brass easily fell out by gravity or a little finger pressure after clearing the gun. FTR, there were no bulges, and the brass and primers looked fine.

It could be my extractor spring is weak. I ordered a couple spares. But there was definitely some higher residual pressure going on while the gun was was trying to extract. Because after changing to a heavier recoil spring, the same rounds extracted and fed fine, and accuracy was much improved. I've put plenty of rounds through it in the interim, and with the proper loads and spring combo, it will run 99.9%. Out of curiosity, the same (presumably overpressure) loads were ace out of my stock FNX (accurate with just an average feeling recoil), but I have since backed off on the charge.

These loads were using AutoComp, which is very slow powder, looking at the burn rate charts. This powder may be testing the limits of the Glock's relatively short action.

[gunnysmith]

If you have reviewed the other post I refered you to:

Probability is, the weakened case web of the reloaded round in conjunction with the unsupported part of the chamber, was the cause, not OAL or any other reloading technique.

[Certaindeaf]

.Probability is, the weakened case web of the reloaded round in conjunction with the unsupported part of the chamber, was the cause, not OAL or any other reloading technique.
Did you miss the part about the measured oal and post 55 etc?
Let's just say that particular one was 1/4" short.. (who knows but what we do know is that measured setback was noted and conveyed) that'd sure blow something up.. except maybe a hipoint.

[Walkalong]

That is some serious over pressure. Sure, you are getting some bullet setback, but is that enough to do that kind of damage? I dunno, I would lean towards a double charge, plus setback, but who knows.

I have posted here before that if a case is bulged to the point my sizer will not size it, I don't want to use it, even if a push through die (bulge buster) can squeeze it down enough to chamber, because to bulge like that, it has to thin when it does.

I also agree with 918v that a little expansion from pressure is completely different than a bulge from over pressure like in the pic he posted (http://www.wingman26.com/images/shooting/glock-brass.jpg).

Glad you are OK. I hope you get your neck tension solved, and perhaps you may want to try a medium speed powder that fills the case more.

[antlermafia]

I have the same exact load set up right now. I'm going to check my oal. Feeling nervous about shooting them in my Glock 22 and 23. Shot about 500 so far with no problems. My powder weight doesn't go over 4.8

[GLOOB]

I find it telling that with AutoComp, I'm getting crazy signs of overpressure (insane recoil and failures to extract), and I'm still not even getting Glocked brass. No smilies. Not even a lopsided bulge that comes close to what I see on some of my range pickups.

Then with a powder like Titegroup, people are getting kB's out of the blue. (Universal also seems to have a bad rep in this caliber).I wonder if there's any relationship between Glocked brass and kB's, at all. Because it seems like whenever a kB is reported, it just came out of nowhere.

[gunnysmith]

brass was once fired from a police range pickup. Brass was then tumbled in a Thumblers Tumbler with SS media, 1 gallon of water, Lemishine & Dawn. After drying, bases were lubed, run through Lee De-bulge kit and then through each station of my setup. Station 1 = deprime/resize, Station 2 = prime/bell, Station 3 = powder, Station 4 = powder cop, Station 5 = seat/crimp. The reloader is a Hornady LNL AP and the dies are Hornady.

I'll let this speak for me as far as reloading buldged cases from unsupported chambers

http://i73.photobucket.com/albums/i221/gunnysmith/Misc%20gun%20stuff/40SWWEBTHINNING.jpg

This is the sectioned resized case, the weakness is still there

http://i73.photobucket.com/albums/i221/gunnysmith/Misc%20gun%20stuff/10mmsmilied.jpg

[Certaindeaf]

Setback is not good. Setback is serious. These days, it's common to coalshovel found/used range brass for general/peersonal use. There's no law against that, of course, except for the laws of physics. Heck, who knows what your paid for "once fired" pin tumbled/hardened brass really is? It sure is shiny though! anyway

[Neutered10mm]

Based on the picture of what is considered "bulged", I'd definitely never try and resize that! All my brass is regular expansion bulges with nothing nearly as gnarly as what was pictured in post #44 by 918v. Anything with a pin divot or neck ding is tossed!

Also, my G27 was a Gen 3 and the barrel issues that are notirious are from Gen1 Glocks ... yes they are all unsupported, but only slightly so after Gen1 barrels were retooled by Glock.

[gunnysmith]

This is serious over pressure

http://i73.photobucket.com/albums/i221/gunnysmith/Misc%20gun%20stuff/glock1.jpg

http://i73.photobucket.com/albums/i221/gunnysmith/Misc%20gun%20stuff/22kb.jpg

This is appears to be chamber pressure gas cutting from a weak case wall OP’s Original photo
http://i73.photobucket.com/albums/i221/gunnysmith/Misc%20gun%20stuff/2012-02-2620at2018-14-09.jpg

[MtnCreek]

The tool marks from the slide are clearly printed on the case head. This cartridge was way over pressure.

[sellersm]

TiteGroup is a very fast powder (14), especially when compared with AutoComp (43). TiteGroup's pressure development is NOT linear, it spikes badly when pushed.

I'm not surprised that the results from the TiteGroup's pressure spike was much more severe than the AutoComp...

[gunnysmith]

The tool marks from the slide are clearly printed on the case head. This cartridge was way over pressure.
The OP's next picture down doesn't support that.
no tool marks what you see is streaking in the carbon in the first picture.

[MtnCreek]

Maybe so. What about the major extrusion of the brass? To me, that says major pressure issue. Would that kind of extrusion be consistent with your theory?

[gunnysmith]

Melting Point of Brass
Between 900 and 940 degrees C.
melting point of 4130 steel melts at about 1300 °C
A set back of the bullet does increase pressure to that there is no doubt.
The combination of weakened case wall and the unsupported chamber in the Glock appears more likely.
I am only suggesting, if the chamber were fully supported, this may not have happened.
There was a reason Glock specifically voids the warrantee when reloaded brass is used and the firearm fails.
They were built for a military contract originally, reloading was not in the equation for the original design.
Glock is more fully supporting the cartridge as they introduce their revisions.
Some After market barrels do fully support the case.

[eam3clm@att.net]

FastCougar
What headstamp are the rounds left in the magizine that were set back (Federal or Winchester)? I will add my expierences to loading the 40s&w for Glocks it is a long story but be patient. I started out with the berrys 180gn rsds bullets and when I ran low I got some of the Rainers because they were on sale at midway and I was already making an order. When they arrived I found them to be slightly smaller in diameter than the Berrys and they miced at almost .400. At the time I had a good supply of winchester cases that I loaded them in with no problems, but once they were gone I reordered Berrys and used them for the next few years. Since then my department switched to the Federal American ammo for training so now my supply of brass is Federal. Recently Cabelas had the Hornady xtp bullets on sale so I stocked up. When I went to load them in some nice nickel plated remington cases I was unable to get a good neck tension. I even tried not belling the case. I then tried the federal cases and still the same problem. I could easly push the bullet in the case. I only had a few winchester cases left, but my neck tension was good with them. My dies are lee carbide dies and they have loaded around 8000 rounds. With this in mind I began to think that maybe my resizing die was worn and needed replacing. I called Lee and was told to send the die in. I started to but the set up is perfect for my cast bullets as it doesnt lead. A smaller resizing die will size the case smaller which may swage the cast bullet down and will cause leading. I put the xtps on the back burner until I could come up with some more winchester cases (I still havent). Another call to lee revealed that they do offer an undersized resizing die. I was told that they run about .003 smaller than their normal die. I ordered it and am wating for its arrival.
To sum all of this up The resizing die sizes the outside of all cases to the same diameter. The inside diameter will depend on the thickness of the brass. Thinner brass has a larger inside diameter, while thicker brass has a smaller diameter. MY collection of federal brass is thinner than what little winchester brass I have left, therefore it produces less neck tension. It is common knowledge that remington brass is thinner.
Now lets look at your problem. You most likely had and problem with too much pressure. Too much pressure can be caused from too much powder, wrong bullet weight for powder charge, and COL/bullet setback to name a few. You said that you were sure of the powder charge and the powder cop would show if the case had trash in it when loading. Ididnt check the load data and I would assume that you worked the load up or are at the starting load. You are using once fired brass from a police range so it was most likely fired from a glock. But keep in mind that it still could have been reloaded once before (I shoot my reloads at a Police firing range, but I always mark my brass). I would say that you are on track with the theory of bullet setback based on my expierence which is Federal brass is thinner which provides less neck tension. Rainer bullets are sized closly to jacketed diameter of .400. Using federal brass with jacketed bullets I was unable to get enough neck tension. What head stamp were the rounds left that setback?

[Neutered10mm]

There are a ton of questions in there, so let me pick through this and answer them in order to the best of my ability. I have a full 5-gallon bucket full of range pickup from my buddy who was the range master at a police range locally for years and years. Anyway, point is, it's police issue (most likely single fire). I have about half the bucket in various stages of clean. I begin with my SS media separator where I tumble the crap out of the dirty stuff to knock out dirt/grime/rocks/grass/etc. I then give it a second rinse and sort it into caliber by hand. Once sorted and I have a full 6qt tub, I set that aside and begin tumbling ... at this point, I haven't done any QC. Now, after tumbling, I load all the rounds neck up in 50 count Federal Champion Wall-Mart special trays (I bought 1,000 rounds from Cheaper Than Dirt about 3 months ago). These trays are great for orienting the shells for inspection. I then give them a good once over mouth up looking for any dings or nick on the case mouth and any creases on overly squared mouths. Once I toss those in the recycle bin, I flip them all head up on a paper towel lined cookie sheet. At this point, I can discern head stamping and overall head condition. Based on this procedure, I'd care to say I have about 90+% federal brass with the remaining being Winchester or PMC ... every now and then the odd duckling shows up. At this point, I knock them all down and roll them around to check the case body for any dings or gouges that look suspect and weed them out into the recycle bin. Finally, I lube it all and place it in a bin marked "ready to de-bulge". That is then de-bulged one by one so I get a 2nd set of eyes on the brass ... anything that's super hard to pass is thoroughly inspected and tossed if it looks suspect. Once that's done, it goes in a bin marked "ready to load" and sits next to the reloader. I then pick them out one by one and feed the cases into the AP, making this the 3rd time I've see it ... at this point, I feel pretty damn confident that nothing suspect has gotten through the inspection process.

Now, that being said ... I have modified this process as I have been reloading and I didn't always de-bulge and in fact, loaded a few rounds that I later pulled apart since the resizing exhibited signs of the "folding over" of the bulge being pressed. I loaded up 100-150 rounds this way prior to adding the de-bulge process into the mix. I have yet to see a single case with a crease since and anything I saw before was removed.

As for how many rounds have I shot reloaded? I can tell you exactly ... I reloaded 550 rounds ... this was the very last box (on the bottom of the stack, making some of my first loads I think), I had one box of spent rounds with 3 rounds in it as well as this full box of 50 left. So I have approximately 500 rounds fired since I began reloading about a month ago.

All 50 of these rounds had Federal head stamps. Like I have said in a prior post, I have adjusted the die once since and everything I have produced lately (dummy round today for example) passed the push in test. I got around to testing the pressure required and while not exactly scientific, I was able to test the pressure required to setback the bullet of the remaining 35 that were not fired or in the mag that exploded. The bullet starts to slip between 35-50lbs. of pressure applied on a bathroom scale that is accurate to .1 lbs.

This is all I have been thinking about all day and the more and more I mull it over, the more I keep coming back to the crimp, setback and charge. I remember just how finicky the scale was measuring and getting TiteGroup to meter consistently ... leading me to believe that my 4.8-4.9 charges could have easily been overcharged to 5.0-5.2 range with the cop die showing much signs. I'll do some more measuring test and get video/pictures of my findings. BTW, my dummy round I was pressing on so long and heavily that the scale turned itself off after ramping past 75lbs. and no give in the bullet. I'm going to test on a 165gr personal defense round to compare, but I think my current setup is golden and these rounds were from an early run and possibly could have been one with a creased bulge on resizing.

One thing is for certain ... It has taught me a new found respect for just how "on the line" these things can be and it's a dangerous game to play if you do so lackadaisically. I had no idea Tite Group was such a hot powder as I went to a shop and asked for the shop reloader's recommendation. He knew I was new and I took his suggestion without prior research ... that WILL NEVER happen again. My lack of knowledge on the subject of this powder's characteristics nearly cost me my hands ... considering I'm a programmer by trade, that would make things even worse!!!

[biogenic]

biogenic ... leading and leading ... don't you just love the English language :D

In context, I was led to believe ... leading me to believe. Also, if you have any press experience or work in the graphic design field, leading is also the space between lines of text because movable type from the 16th century up until digital presses were invented used lines of lead to gap the font "slugs" ;)

You are hilarious...

[GLOOB]

I had no idea Tite Group was such a hot powder as I went to a shop and asked for the shop reloader's recommendation.
That reminds me of the day I bought my first reloading supplies. I had done some research on different powders and thought I might like to start off with Universal Clays. When I asked the guy helping me, he looks confused and tells me that's a shotgun powder. He was very knowledgeable about the reloading dies and presses, so I second guessed myself and ended up going with something else.

Fast powders like Titegroup are very popular with reloaders, even in 40SW. It's partly cuz lots of reloaders like light plinking ammo that's very accurate with very little recoil and with very little powder. If you tried to load a slower powder that light, you wouldn't get the same accuracy, cuz slower powders don't build enough peak pressure to burn consistently at that low of a charge. At least, in general. I made up some HP38 loads in 40SW for fun (another fast powder), and I didn't see the point. It felt like shooting 9mm. I might as well actually shoot 9mm and save some money.

[Walkalong]

Before giving away my last .40, I used 700X for light loads. It worked well and is much bulkier than Titegroup.

We do not know if this was a double charge or not.

[243winxb]

I was able to test the pressure required to setback the bullet of the remaining 35 that were not fired or in the mag that exploded. The bullet starts to slip between 35-50lbs. of pressure applied on a bathroom scale that is accurate to .1 lbs.
This would seem to rule out set back or neck tension as being the cause. SAAMI list COL at 1.135" max to 1.085" minimum. http://www.saami.org/PubResources/CC_Drawings/Pistol/40%20SandW.pdf

[Certaindeaf]

This would seem to rule out set back or neck tension as being the cause.
Except for the fact that five of these were in the magazine after the kb. They seem to be setback and are overpressure because of it.

http://www.thehighroad.org/attachment.php?attachmentid=160030&stc=1&d=1330364308

[MtnCreek]

If you formed a crease in the brass on sizing, that would be very bad. I've had some Speer LE ammo that was police range once fired; they looked to be very hot factory ammo. They could have been reloads, but that's not how they were sold to be and did not appear to be reloads. Some of them had a pretty bad belly in them. If I had to guess; they were hot factory ammo shot through a Gen 1 Glock or some LEO had monkeyed with his feedramp. I sized them with regular dies and checked them with a case gauge; any failures were discarded.

I still think your KB was caused from a massive overpressure, whether over-charged or from setback.

IMVHO, this is what I'd do: Revisit my entire loading procedure (you’ll have to do this to get yourself comfortable with loading again). Use a slower powder (HS6 would be a good one). Sell all this 'unknown' brass and use that money to purchase new brass. Keep the new brass in lots and record how many times they were fired and whether they were fired as low-end plinkers or HV loads.

[Certaindeaf]

I like it when my rounds look like coke bottles. I wonder if the Lee FCD irons that out.. never used one.

[Neutered10mm]

I'd also like to know this as well since I already have one, just not using it in the AP, only the cheapy de-prime/de-bulge press I have setup.

[Gonzofam]

I would say in conjunction with all except the bitter guys, one long shell will give you that wrong kind of boom. I have caught a few. 3 to be exact. Now when belling i look for the ones with a bigger bell or the bullet just flows like a marble in a bucket. This can also happen with thin er brass in the batch. Good luck and stay vigilante. Good luck in the future and glad you did not get injured.

[rsrocket1]

Just a couple of "reality check" questions:

Are you able to take a measurement of the length of the KB case? Not too long, right?

The barrel of the gun is clear of obstructions, right?

Glad you're OK.

[Certaindeaf]

Just a couple of "reality check" questions:

Are you able to take a measurement of the length of the KB case? Not too long, right?

The barrel of the gun is clear of obstructions, right?

Glad you're OK.
A little reality check for you.
He posted a pic of the kb case, right? Of course he could take measurements of it because he posted a picture of it and of a caliper.. it must be long because of the crack and flow, right? Check it out.

[Neutered10mm]

It flowed all right! It flowed the case body down into the web and then they both nearly made the extractor grove disappear. The overall outside diameter formed itself to the exact size of the Glock chamber, which we all should know by now has MUCH looser tolerances than most other manufacturer's barrels. I had to extract it from the barrel with a flat head screwdriver after getting the barrel separated from the slide with some massive blows with a screwdriver (brass & nylon punches weren't working) and a 2lbs. dead blow hammer. Took about 6-8 hard strikes. So yeah, I don't really see the point in measuring it :D


http://www.thehighroad.org/attachment.php?attachmentid=160026&stc=1&d=1330363685
beget
http://www.thehighroad.org/attachment.php?attachmentid=160029&stc=1&d=1330363835

[crazy4milsurps]

HOLY SH*T!!!!

I never crimp any of my loads not so much for fear of a KB but more so because I never noticed any real benefits to crimping. I'm not saying there are no benies, I just never noticed any. glad you're ok and that sucks about your gun

[GT1]

Hey FastCougar, thanks for coming forward and posting about your KB. They happen, and it is a good wake up call for guys like me(I'm pretty new) to pay close attention to what we are doing.

Glad no one was seriously hurt. :)

[Certaindeaf]

^
True. This is an excellent and well put forth learning lesson for us all. Thank you, FastCouger. We all learn from each other.

[powell&hyde]

Wow, glad your ok FastCougar.

[918v]

Did he ever pull the loose bullets to see what their diameter was? That's the source of the setback problem.

[Neutered10mm]

I pulled 3 of the 5 apart and they came apart with 2-3 blows of the hammer ... the dummy I produced wouldn't slip the bullet and took 8-9 blows ... same bullets (Ranier 165gr hp double struct plated) ... I'll head down now and measure.

[rsrocket1]

Certaindeaf- thanks for taking the high road.

I just wanted to make sure the KB did not occur due to an obstructed barrel. I've been following this thread and may have missed that post, I am only trying to help.

If the case was too long or the crimp too severe, he may have caused the brass to get trapped between the barrel and the bullet causing severe overpressure.

Then again, he may have been distracted when showing his son the reloading procedure and accidentally double charged or over charged a case. Whenever I have an interruption in my loading, I start all over again as if I just started a loading session. I check everything and run several cases one station at a time and measure/weigh everything.

I also hear of many many kabooms due to Tightgroup because a double charge does not spill powder all over the bench. I understand the risks because I use Bullseye which also uses fairly small charges in some deep cases such as .357.

My guess it that a serious overpressure caused this because a simple blown belly would blast the bottom of the case out, blow out the magazine and not split the barrel.

I've read of people shooting normal charges out of split cases and in the case of a fully supported chamber, nothing happens. Firing out of battery and case head separation (not this particular situation) tends to blow the unsupported part of the case and not split the barrel.

[Certaindeaf]

Certaindeaf- thanks for taking the high road..
No problem. It seemed you were being condescending/demeaning. I try.
I think we all wish our reloading brother the best.. perhaps I was too quick on the (very genteel) trigger.

[Neutered10mm]

Bullets are spot on .400, both new and those 3 pulled from the 5 remaining in the mag. I made another dummy round, measured it out with a neck of .423, a waist of .419 and a web of .423, and finally an OAL of 1.131. I then put it on the scale and began leaning into it as hard as I could (53.7 lbs) with my thumb and then measured OAL again ... 1.131 ... didn't budge!

The current press setup is spot on. I now know that these were early rounds and more than likely this was caused by over belling, and then subsequently the "crimp" contributed to diminished neck tension, which caused the bullet to setback during recoil and chamber feed. I also tested some of the remaining 35 rounds from that batch and again, the bullet starts to setback under around 30 lbs. of pressure with my thumb on pressing the bullet against the scale.

Make of that info what you will because I don't think there is a bathroom scale thumb press pressure standard :D

[Neutered10mm]

rsrocket1 - The round wend down range and hit about 6 inches down and left of the bulls eye.

I've been holding out on you guys ... I have the event on video ... here are two successive screen grabs. The first is of the round exploding, the second is of the round down range.

http://www.thehighroad.org/attachment.php?attachmentid=160087&stc=1&d=1330449602

http://www.thehighroad.org/attachment.php?attachmentid=160088&stc=1&d=1330449602

[MtnCreek]

Anybody know how much force is placed on the cartridge when hitting the feedramp and from recoil in the mag??? Anyone care to take a guess at how that would compare to the impact the cartridges in the mag took during the KB???

Mr. Cougar, You're still holding out on us. Where's the screenshot from when you turned to the camera with a dazzed look? :D

[Neutered10mm]

LOL, after the gun flew from my hand as I stumbled back into the camera, the wife who was holding the camera continued to film as I "walked it off" while the range master climbed over the bench and assessed the situation. My hands felt like they had frostbite for about 2 minutes - a severely painful tingle/numbness - hard to explain. Sorry to disappoint, no such film exists :D

[PO2Hammer]

Why don't you just feed the dummy rounds into the gun from the mag to subject them to the same forces they will encounter in the feed cycle?

Impacting the feed ramp is not the same as pushing on them with your thumb.

[gunnysmith]

When you take the cartridges apart, would you check the interior of the case to determine if there is a "lip" where the "buldge" was removed.
I would greatly appreciate it if you could.
To this point in my reloading I have not used Bulged cases nor attempted to remove them.
I have only one pistol with an unsupported chamber.

[gamestalker]

As stated by others here, the crimp station or step in seating bullets for an auto loader straight walled case, is not to enhance or produce neck tension. Straight walled auto loader cases such as the .40 S&W head space at the mouth so distorting the mouth by crimping is going to have the potential to cause serious problems as follows, and as you've unfortunately discovered.

If the case mouth is closed too much during the removal of the belling step, the entire loaded round can chamber too deep in the chamber which would allow the mouth to get pinched in the throat. When the mouth gets pinched, it can't expand during discharge, thus delaying or preventing the gases and bullet from escape freely from the case, the result is a KB. There are other undesired effects less catastrophic, yet still potentially dangerous, or damaging to the firearm.

Something that may not be acceptable for everyone, as it could possibly restricted by the type of press or bullets being used, is to seat bullets without belling the mouth. I've been doing it this way for at least a couple of decades. I make sure each case mouth is reamed and chamfered and since I don't load non jacketed bullets the need for belling the mouth is unnecessary.

However, if you are going to bell the mouths, make certain that the die is adjusted just enough to only remove the bell and not actually effect a crimp. neck tension for AL cartridges is 100% produced by the resizing die producing the correct internal mouth/neck dimension, not the crimp.

Also be careful not to bell the mouth more than is necessary to allow the bullet to seat without shaving and no more.

[Neutered10mm]

would love to test feed the rounds in my glock ... oh wait :D

[Neutered10mm]

OK, first and foremost, I think the term "bulge" means drastically different things to different people. For example, a new reloader/shooter like myself, I call this a bulge, whereas some here might consider it "expanded".

http://www.thehighroad.org/attachment.php?attachmentid=160100&stc=1&d=1330456677


http://www.thehighroad.org/attachment.php?attachmentid=160101&stc=1&d=1330456677

However, when I run it through the press WITHOUT running it through the Lee de-bulge kit first (with Lee FCD w/internals removed), I get this crease in the web area. Said crease is substantial enough to feel with the finger nail:

http://www.thehighroad.org/attachment.php?attachmentid=160102&stc=1&d=1330456699

brass that has been de-bulged does not show this crease.

Back to what some consider a bulge and what other consider expanded ... what would you call this brass? 99% of my brass looks like this ... the other 1% does as well, but is getting tossed due to neck dings and such ... nothing nearly as bulged as this:

http://www.wingman26.com/images/shooting/glock-brass.jpg

[Neutered10mm]

As stated by others here, the crimp station or step in seating bullets for an auto loader straight walled case, is not to enhance or produce neck tension. Straight walled auto loader cases such as the .40 S&W head space at the mouth so distorting the mouth by crimping is going to have the potential to cause serious problems as follows, and as you've unfortunately discovered.

If the case mouth is closed too much during the removal of the belling step, the entire loaded round can chamber too deep in the chamber which would allow the mouth to get pinched in the throat. When the mouth gets pinched, it can't expand during discharge, thus delaying or preventing the gases and bullet from escape freely from the case, the result is a KB. There are other undesired effects less catastrophic, yet still potentially dangerous, or damaging to the firearm.

Something that may not be acceptable for everyone, as it could possibly restricted by the type of press or bullets being used, is to seat bullets without belling the mouth. I've been doing it this way for at least a couple of decades. I make sure each case mouth is reamed and chamfered and since I don't load non jacketed bullets the need for belling the mouth is unnecessary.

However, if you are going to bell the mouths, make certain that the die is adjusted just enough to only remove the bell and not actually effect a crimp. neck tension for AL cartridges is 100% produced by the resizing die producing the correct internal mouth/neck dimension, not the crimp.

Also be careful not to bell the mouth more than is necessary to allow the bullet to seat without shaving and no more.
you have nailed it ... I suspect that this round of bullets was from over belling and then subsequent over crimping ... again, showing my son the process, I think I forgot to reset the press. I then made the potentially fatal mistake of not redoing any of the rounds after resetting the press. Apparently my changes have worked quite well as my "bell" is barely enough to get the bullet to wedge into the mouth, barely measurable, and my rounds produced since fired excellently. My recently produced dummies are measuring coke bottle specs with a "waist" about .010 less than the neck or head. Knowing the potential for disaster, I can confidently say that I now know what to look for and what not to do in my routine to produce safe rounds.

[Neutered10mm]

^^ forgot to include my reasoning for the "nailed it" ^^

I remember pulling a VERY tiny ring of brass out of the barrel after removing the shell ... I don't have a pictures of it, but it couldn't have been more than .01" thick ... can't believe I had forgotten to mention this! Is that a Tell tail sign of what you are describing? Sure as hell sounds like it to me ... damn, still can't believe I forgot to mention this (had to go back and read everything I had written concerning my retelling of the event).

[GLOOB]

A ring of brass in the leade of the chamber? Yeah, that sure sounds like the culprit.

Here's another oddball to watch out for. I have NO CLUE how I didn't notice this while seating.

So I'm out shooting and my G27 has a jam. I rack the slide, and the round chambers. I pull the trigger and get a click. When I jack the round out, the nose is setback nearly flush with the case mouth!

Somehow I managed to fill an unsized case with powder, seat a bullet over it, load it into a magazine, and then get it chambered (even though it set back so far it tried to jam on the feedramp, and I still didn't notice). I wouldn't have thought this many mistakes was even possible. :)

So there are more than a couple ways to kB a gun out of the blue without doublecharging. This is one reason I wouldn't consider decapping with a universal decapping pin before sizing, unless I had a good reason.

I understand one of the reloading companies only accepts customer brass with primers still in them. I always thought it was so they could tell if it was once fired or not. Now I wonder if it's to reduce the chance for making a mistake such as this, but with a live primer.

[PO2Hammer]

would love to test feed the rounds in my glock ... oh wait
I figured you must have another .40 if you're still cranking out .40 ammo.

[rsrocket1]

I remember pulling a VERY tiny ring of brass out of the barrel after removing the shell ... I don't have a pictures of it, but it couldn't have been more than .01" thick ... can't believe I had forgotten to mention this! Is that a Tell tail sign of what you are describing? Sure as hell sounds like it to me ... damn, still can't believe I forgot to mention this (had to go back and read everything I had written concerning my retelling of the event).

I think we have a winner. An over crimped case causing it to get the case mouth pinched between the bullet and the barrel and a serious overpressure. Caused by a halt in the normal reloading routine and a distraction.

An expensive lesson, but thankfully no permanent loss of people or major injury.

[Neutered10mm]

I haven't produced any ammo since this happened this past weekend ... the only thing I have done is produce a few rounds to test my press setting and retest my rounds as we have been discussing.

[jr_watkins]

FastCouger, you bring up the exact question I have had for years, ever since first hearing about "glock bulge". IMO, unsupported barrel really means "not fully supported" and any problematic stretch in the brass would look like the photo with the bulge isolated to one section. All my 40 brass looks like your photo's, with swelled area just ahead of the thicker base brass. This is the case if shot through a Glock barrel or through a Wilson Combat barrel I have. The brass fails the case gauge test (because it binds at the 360 degree bulge) if reloaded on a Dillon Square Deal B press. the loaded rounds still feed into the Glock barrel, but only some fit into the Wilson Combat (slightly tighter dimension).

Is this 360 degree stretch caused by the "not fully supported barrel" and if so how? The area of the stretch is well forward of the small area that isn't supported. If not, this stretch must be just where the case headspaces and seals the gas.

Can anyone clarify this for me?

[rcmodel]

Note the thicker case web taper further back near the case head.
The most expansion occurs in the thinner case wall further foreword.

http://i81.photobucket.com/albums/j219/rcmodel/KTOG/Caseweb.jpg

It takes some serious over-pressure to make the bubblegum bulge at the feed ramp cut.

rc

[GLOOB]

Is this 360 degree stretch caused by the "not fully supported barrel" and if so how? The area of the stretch is well forward of the small area that isn't supported. If not, this stretch must be just where the case headspaces and seals the gas.

Well, if the ammo is loaded hot enough, and the action opens early enough, the brass can still be under considerable pressure at the time of extraction. It seems like this would be the only way for the brass to bulge that high.

This is one of those things where I wonder if everyone isn't on a different page. The smilies are obviously made by the unsupported ramp area of the chamber. The higher up bulges would appear to be related to the action opening early. "Unsupported barrel" isn't the answer for everything, in MY book. I've tried to have this discussion with a very well respected reloader on the forum, and he seems to think that chamber support is all that matters in this caliber when hotting up your loads. Perhaps it is true when you're using faster powders. But I know I can get my G27 to malfunction with hot loads of a slow powder without making smilies. The chamber support doesn't appear to be the limiting factor in this particular case.

[rcmodel]

A minimum spec cartridge in a Max spec loose chamber will bulge ahead of the web at normal pressure.

rc

[Certaindeaf]

There are two ways to find "tiny rings of brass//copper/lead".. one is by seating the bullet into an unchamfered/unbelled case and the other is upon chambering.. the chamber shoulder could shave some bumped up (from perhaps an overzealous crimp) copper/brass/lead from the bullet itself.
Were it the former, it would have had maximum neck tension and were it the latter, from too little maybe. This in and of itself, to me, given all the facts, is essentially a non-issue.. or poses more questions than answers.

[GLOOB]

RC, I believe you're correct. But I also seem to recall seeing pictures of smilied brass where the crease occurs too high. Is it not the case that a piece of 40 brass can bulge during extraction? I've also seen entire lots of badly guppie bellied Speer once-fired, where the bulge seemed abnormally high, mostly on one side. No creases, but the bulge seemed too far up to be the normal placement of the ramp while the action is closed. But I've never seen a Glock Gen2 barrel firsthand, so maybe it's just the chamber shape, afterall.

[rcmodel]

If pressure were still high enough to bulge a case during extraction?

It wouldn't come out of the chamber and the rim would tear off.

An expanded case is locked in place until pressure has dropped enough for it to contract and let go of it's grip on the chamber wall.

Even blow-back firearms like most .32 ACP's and all .22 RF's have enough inertial delay built in to keep the case in the chamber until pressure drops enough to allow it to be extracted.

rc

[GLOOB]

K, thanks. That sounds good to me.

[Neutered10mm]

Think about what was just said and then consider the length of time a nano-second is ... mind-boggling what goes into slinging lead down range!

[jr_watkins]

RCMODEL...your phrase "feed ramp cut" is much more accurate than unsupported barrel. I'll take it that unless the brass is expanded (damaged) at the point where there is a feed ramp cut, the expansion of the brass up the case where the brass is thinning (by case design) is normal and not a problem. Reloading those cases should be fine provided the brass is not stretched long or thinner by sizing?

[rcmodel]

Yes, you should take it as that.

Expansion to fit a loose chamber in front of the case web is perfectly normal.

The sizing die will completely remove it.

PS: You can also see the same expansion on resized brass, if the sizing die is sizing it smaller then spec to start with.

rc

[Bob72]

Sorry curious......powder cop??? What it is?

[Neutered10mm]

it's a powder charge indicator die: http://www.youtube.com/watch?v=s6koVra3tg0

[popper]

Lessons learned? Don't allow interruptions during loading - a good lesson for the entire family!
Multi-stage presses allow mistakes to NOT get caught. Did that case really get sized? Proper powder dropped? Did you mic the bullets to check for proper size? It was a case separation, allowed the head to push back and blow out at feedramp. I've blown the head off a 40 (failed FC case), no harm to me but 'what the heck just happened' experience. Insufficient neck tension will allow set back or bullet jamming in the lands. Either is a pressure overload and with tightgroup, the spread is 0.5 gr min to max(hodgdon 165 gr). That powder is fast and NOT forgiving. Press the nose with your thumb for a seating check. No it's not 20#, but if it is loose, it will move and you FEEL it. It will be loose because the bullet is undersized, the case hasn't been sized or is really thin (or you used a Lee collet die). Couldn't see the headstamp, just looked like a A.

[Samari Jack]

^
True. This is an excellent and well put forth learning lesson for us all. Thank you, FastCouger. We all learn from each other.
Same here!!! I've learned much by your post. Ignore the bitter X-pert (drip under pressure).

[Neutered10mm]

Thanks ... I owned and operated a car forum for 10 years and understand the importance of sharing success AND failure stories ... I can't thank you guys enough and it's the least I can do in return (share my experiences).

[Certaindeaf]

^
Aha! So you have a Cougar? (the car lol)

[Neutered10mm]

^
Aha! So you have a Cougar? (the car lol)
I had one ... now the other ;)

[ArchAngelCD]

I'm just wondering why when a thread like this comes up three things are always in the first sentence, KB, Glock and 40 S&W???

[jibjab]

I'm just wondering why when a thread like this comes up three things are always in the first sentence, KB, Glock and 40 S&W???
I'm glad I cut my teeth on lower pressure cartridges.

[bds]

I'm just wondering why when a thread like this comes up three things are always in the first sentence, KB, Glock and 40 S&W???
Although KaBooms predate Glocks (plenty of 1911s and other pistol models have KBed before the introduction of Glocks), I think the "stigma" of 40 caliber Glock KBs may have resulted from the popularity of these "Law Enforcement" caliber pistols and greater number of them in use. Simply comparing numbers, there are overwhelming numbers of 40 caliber Glocks being used than other pistols.

IMO, it is only prudent to recognize that KB can happen in any caliber and any pistol (and they have ;)). Do a Google search for "Sig, Beretta, HK, Ruger, etc. Kaboom" and even "1911 KaBoom" and you will find plenty of incidents of non-Glock KBs.

There are several factors that contribute/lead to case failure resulting in a KB. Meet those factors in any caliber/pistol and you will have a KB.

[popper]

Look for pics of rifle case separation, that is what you have. The sizer die is tapered. If it doesn't go ALL the way down or doesn't occur, the case doesn't get squshed enough and the bullet will be loose. Expander and crimper have nothing to do with it. This is a case head separation, the brass flows easily when partially out of battery. Yours wasn't glocked brass. Hot load or loose bullet - probably both. I use the same bullet with hp-38/231 @ 1.110, no problems.

[Striker Fired]

But it's so much fun saying " another Glock KaBoom".;)
I have a couple Beretta .40's and I don't feel their chambers are suported very well.

[Hondo 60]

FastCougar,

First of all, I'm glad you still have all 10 fingers.
That must've been quite a shock when it went kaboom!

Thanks for posting this as a reminder to all of us.
No distractions & double & triple check to make sure you have the right charge & the right crimp.

I had a kaboom in my 1911 last fall. The gun was only a month old or so.
Thank God the only thing that happened was a broken grip.
To this day I'm still not sure if it was from a severe setback or a dbl charge.
Never had it happen before or since. (and hope it never happens again)

Please stay safe my friends!

[mboylan]

That is some serious over pressure. Sure, you are getting some bullet setback, but is that enough to do that kind of damage? I dunno, I would lean towards a double charge, plus setback, but who knows.

I have posted here before that if a case is bulged to the point my sizer will not size it, I don't want to use it, even if a push through die (bulge buster) can squeeze it down enough to chamber, because to bulge like that, it has to thin when it does.

I also agree with 918v that a little expansion from pressure is completely different than a bulge from over pressure like in the pic he posted (http://www.wingman26.com/images/shooting/glock-brass.jpg).

Glad you are OK. I hope you get your neck tension solved, and perhaps you may want to try a medium speed powder that fills the case more.

With TG that much setback is enough to KB. With a more suitable powder that doesn't have an obscenely sharp pressure curve, it is not.

[mboylan]

I find it telling that with AutoComp, I'm getting crazy signs of overpressure (insane recoil and failures to extract), and I'm still not even getting Glocked brass. No smilies. Not even a lopsided bulge that comes close to what I see on some of my range pickups.

Then with a powder like Titegroup, people are getting kB's out of the blue. (Universal also seems to have a bad rep in this caliber).I wonder if there's any relationship between Glocked brass and kB's, at all. Because it seems like whenever a kB is reported, it just came out of nowhere.
It doesn't come out of nowhere. Small variations in loads with very fast powders can cause big spikes in pressure.

[Samari Jack]

Just a bit of info from a somewhat new reloader: I read with interest the bit about bathroom scales and pressing to determine neck pressure/crimp or whatever and bullet setback. I drilled a variety of holes in a block of 4x4 with my drill press to hold securely different calibers. Since I had .380 ACP in my press, I checked about a half dozen of varying neck tension/crimp from obviously a bit loose to way beyond to tight.

They all caved in some more, some less, beyond acceptable limits at 30 lbs on my bathroom scale. My guess is a bigger bullet, like the .40 S&W, has more case wall contact increasing friction and amount of force needed to push the bullet back. Not knowing what amount of force is needed for each caliber, I'm inclined to just use case measurements for now until I find more definitive data.

[Striker Fired]

For .357Sig I've always gone by 40lbs minimum for holding without setback. That number was derived from some tests done to come up with a lb rating of force imparted on the bullet in an average cycle,slide hammering home from an actual firing,not cycled by hand. To read some on it go to
http://www.handguninfo.com/Archive/www.Pete-357.com/factory.setback.chart.htm

[Samari Jack]

For .357Sig I've always gone by 40lbs minimum for holding without setback. That number was derived from some tests done to come up with a lb rating of force imparted on the bullet in an average cycle,slide hammering home from an actual firing,not cycled by hand. To read some on it go to
http://www.handguninfo.com/Archive/www.Pete-357.com/factory.setback.chart.htm
From the link you provided: "To show you how strong the 357 Sig cartridge really is, as well as how sturdy the Glock 31 is, I test fired a series of cartridges that I "purposely" made with major bullet setback (see charts below).

Glade there are folks with this much confidence to supply data but not my cup of tea.

[918v]

Measuring bullet setback using a bathroom scale is a bit crude.

I measure bullet setback by making a few dummy rounds and running them through my gun. I see about .004" to .006" of setback after ten feeding cycles from the mag. This is the only way to check.

[Striker Fired]

Yes it is quite bal**y to test setback and post it . I wouldn't take those numbers and load by them. For the bathroom scale test,I believe it is good,as long as you do double check,as has been said, by repeated cycling of a fair number of rounds to get true measurements. That way you should be able to know if "40lbs" is sufficiant or if you need 45, or 50lbs.

[918v]

You find .006" of setback after 10 trips into the chamber unacceptable?

[Bob72]

Glad nothing lost in the KB. Here is an article that I was referred to and might help on set back issues.
http://www.handguninfo.com/Archive/www.Pete-357.com/factory.setback.chart.htm
He has several excellent articles on 357 Sig for those that shoot it.

[T Bran]

If I was really being pickey about neck tension. I would have a nut welded to my press handle and use a torque wrench to compare your ammo to factory. With the ammount of leverage generated by a press it will probably be best to use one calibrated in inch pounds.
Just a thought for those who really want something more consistant than a bathroom scale. I just press mine on the bench once hard and measure them.
Glad to hear you werent seriously injured.
T

[Neutered10mm]

Just a followup to keep all those informed. I have a new screen name as well as a new pet load that I'm now shooting (4gr. TG, Rainier 165gr. RNFP). I also FINALLY got the Glock back from the factory and I think they didn't bother to inspect the barrel ... Check out these two videos and pay attention to the tail end of the first video where I put 14 rounds through the G27 (trigger is factory horrible and it shows in my shooting). 2nd video link (3rd in series about my new load) goes into great detail about what happened at the range with the Glock and why I stopped at 14 rounds ... tell me what you think. Matter of fact, I started a YouTube channel to document everything gun related for me and I plan on doing a weekly video (at minimum) ... please take a second to subscribe to the channel and leave any comments there. Let's go ahead and let this thread die like my poor Glock frame ;)

http://www.youtube.com/watch?v=_oK11iRjyqM

http://www.youtube.com/watch?v=_Vz1w2hqj6U

[gamestalker]

I think the crimp for these type cartridges is probably one of the most mis-understood elements of reloading. The crimp for these type cartridges, being those that head space at the mouth, is not intended to produce or even increase necessary neck tension.

From what it sounds like to me you applied to much crimp which reduced the diameter of the case mouth so much, that the mouth became pinched in the throat when it was chambered and fired. A pinched mouth will certainly increase pressures enough to KB most any firearm. Imagine what happens when the bullet is delayed by just a fraction of a second from exiting the mouth? KB

A suggestion I think more new reloaders should consider, is to pick up your reloading books and read them to the extent that you understand the difference between various cartridge designs and how these differences apply to reloading. On the flip side, a case that head spaces on the rim is reliant on a firm crimp to prevent bullet set back or jump. Read your reloading books. Your fingers, eyes, guns, and lives depend on it.

[TheCracker]

I just read about 100 posts on this thread and have had enough.

Anyway, I don't understand why a reloader would reload for a glock 40 cal with a unsupported chamber or even use brass that had been shot out of one. It just doesn't make good sense IMO.

My .02 cents would be if you have to have a glock and want to reload for it replace the barrel and reload ONLY brass you know hasn't been shot out of a glock

[Striker Fired]

It ok to reload for a Glock .40,plus use brass shot out of a Glock(or other brand that are not fully supported)as long as reasonable judgements are used and followed as far as how "hot" to load them,or how much of a "bulge" is too much to resize.It is all in the hands of the person doing the reloading and what chances they feel are safe.
I myself,just don't care for max or even near max loadings,unless for certain circumstances. That way there is more room for variances.

[elwoodm]

nobody said anything about what the brass was trimmed to or did i miss that part. all that sizing and debulge had to increase the length somewhat. just a thought if too long and too much crimp that would sure put some brass in the barrel.

[Striker Fired]

The .40 S&W headspaces off the mouth,so it wouldn't matter if the brass was 1/2" too long,it still wouldn't put the case any further in down the throat than a correct spec case.

[Bovice]

You should be aware that your new "pet load" is below the minimum charge.

[Walkalong]

if the brass was 1/2" too longTypo?

[Neutered10mm]

for a jacketed bullet ... plated bullets should be loaded with lead cast bullet data, at least that's what Rainier suggests. The recommend starting at the mid point and adjusting accordingly. As for plinking or target loads, you can go as low as will cycle the slide reliably and going hotter proves nothing other than the laws of physics.

As I stated in the latest video at the end, I plan on adjusting the charge .1 grain lower for a few shots, then keep doing so until I hit that point with the M&P (won't cycle reliably). I'm retiring the Glock's barrel in exchange for a 9mm conversion barrel, but before doing that, I plan on getting a Chronograph to see just how slow this pet load is.

[atblis]

I've always wondered if the bullet setback KB thing has something to do with the powder being used. I'd be curious to see a pressures measured for 40 S&W with various COAL (simulating setbacks) and various powders. My guess is that we'd find that some powders are much more sensitive to setback. Anybody ever heard of a 40 S&W Kb with Unique?

[Walkalong]

Neck tension, neck tension, neck tension............

[Hammerdown77]

I'd say the 40 S&W is one of the worst rounds for bullet setback. Especially if you are loading mid to upper level pressures. There ain't much room left in the case, so if the bullet gets pushed back in, pressure skyrockets. 9mm is the same way.

Neck tension is critical. Crimp doesn't improve neck tension. In fact, in the case of lead bullets, it usually reduces it.

The 3rd gen Glock barrels have as much case head support as a Lone Wolf replacement barrel. Or at least they are really darn close. I know that surprised me when I had the two sitting side by side on my bench.

[brickeyee]

Check the size of the expander.

Removing a few thousandths of an inch may well increase case tension enough.

The case ID should be at LEAST 0.002 inches SMALLER than the bullet OD.

The case tension is created by forcing the larger OD bullet into the brass case.

[atblis]

Remington brass?

[gamestalker]

What RC said!! Use a slower burning powder and you'll greatly reduce the possibility of over charge or bullet set back causing enough pressure spike to KB.

And regarding crimp, only crimp to the extent that you have returned the mouth back to it's near starting diameter or you will teater on pinching the bullet in the throat!

[Waywatcher]

Is it realistically possible to have excessive neck tension?

My .40 loads use a 180 grain Hornady FMJ and 6.4-6.5 grains of Power Pistol.

I made a few dummies and measured the OD of the case body before loading the bullet, and after, and in all cases it expanded 0.002 of an inch. I put what I think is a light taper crimp on the dummies--I crimped until the OD of the case mouth was about half-a-thou smaller than the case body. I aimed for an OAL of 1.125 and this ammo functions perfcetly in Glock 23.

With all that explanation out of the way, I rechambered one dummy over and over again, holding the slide all the way to the rear before letting go completely. I repeated this Forty (40) times and the OAL had only shortened by 0.002 of an inch?

Sound acceptable? The Hornady FMJs have an additional angle compared to a hollow point, and I hypothesize that it limits setback because all along the "extra" angle connecting the ogive to the meplat the bullet has what I would call in metal finishes "hammer beaten" appearance after forty chamberings.

[Neutered10mm]

KaBoom video is up: http://www.youtube.com/watch?v=_q9O-wVfQ-s

[Neutered10mm]

Load Data:

Case: Federal (once fired - bought rounds and fired myself)
Primer: CCI 500
Powder: 4.9 grains of Titegroup
Bullet: Rainier 165 grain HP

Video description explains exactly what happened. Over bell removed all neck tension as the die wasn't a under-sizing die. Over crimp turned the mouth inward, impeding the barrel throat as well as causing setback ... pressure had only one way to go before it could overcome the resistance. Round landed on target lower left @ 7-8 o'clock position.