Rounds no good after chambering?

[Skylerbone]

I've seen setback before and it was noticeable without calipers. Happened with a friend who had started loading a few months earlier (200 gr. SWC). He was carrying them as SD rounds and unloading to clean.

Many people with expensive equipment have been paid good money to test pressures and provide exacting specifications and specs. I like following those guidelines because I love my hands, fingers and eyes. There's a reason reloading involves calipers instead of inch rulers.

 

[GLOOB]

Easy, don't buy a Glock if you don't want your gun to explode

Actually, there's an easy solution if you HAVE a Glock, in particular:
http://s688.photobucket.com/albums/vv241/gloob27x/?action=view&current=g.mp4
Try this with your Sig, XD, or 1911.

I believe it was the fine print on the back of a box of Speer Gold Dots I read, which stated the ammo was designed to withstand 4 chamberings. That seemed very specific to me. So I took out the calipers and started racking in rounds. Of the few I tested, it was like clockwork. The OAL was the same, same, same, same.... then it started to measurably shorten on the 5th or 6th chambering. (Yes, Jim. This was factory Speer Gold Dot ammo, and it shortened after 5 chamberings!) But it was by a couple thou, or so. It didn't get into where I would think it dangerous, even after a dozen chamberings.

Apparently Lyman did some testing that showed it was possible to double the peak pressure in a luger cartridge by setting the bullet back 0.03" That's quite a bit of setback under very specific conditions, though.

 

[Jim K]

Notice, I specifically said that I tested with FACTORY ammo. Reloads can have little or no case tension, little or no crimp, can have a double charge, can have the wrong powder, etc. Even so, I remain skeptical that a bullet pushed into the case, and that alone, can cause high enough pressure to blow up a gun. I think the gun manufacturers are doing a CYA act in warning against the multiple load "problem" because they don't know what really causes those blowups. (I have a suspicion that it results from a 9mm round accidentally put into a .40 chamber, then a .40 round jacked in behind it.)

Anyone remember the "medium load" blowups? Supposedly, a light to medium load in a rifle could cause some kind of high pressure "wave effect" and blow up the rifle. It seemed to happen only to those who bragged/complained the most and who always seemed to want new rifles from the ammo make, component maker, etc. No one else could duplicate the condition and when new rifles failed to materialize, the "problem" went away.

Jim

 

[Thlax]

Now what about if your release the slide by hand in a controlled manor (ie:not letting it slam) compared to just dropping the slide via hand or slide release without control. Difference to ammo?

 

[Manco]

Interesting. If you follow the guidance given to NOT re-chamber a round, what are you supposed to do with it? Toss it? Break it down and reload? I'd suggest you should measure the OAL and then if too short, break it down or toss it.

At minimum, I'm sure that any round could be chambered several times with virtually no risk--maybe even dozens of times with only slightly greater risk. So I don't think it would hurt to put it aside for range use after one chambering (or a few), whereupon it will only get chambered one more time.

Along with RDF what are you supposed to do... Say I'm carrying SD ammo, go to the range, eject my 1 SD bullet and mag then put in Blazer. Does that loaded SD round become trash? Should I just shoot it at the range that trip?

Sure--fire away! Or you could try keeping count of the chamberings or inspecting the round, but I like to keep things simple myself.

Let me see if I got this right. I take my set-a-sides measure the COAL, find that they are within tolerance and the next re-chambering will drive the bullet so deep that it will blow up?

Well, I always had the feeling that the bullet may sometimes not move at all until it got loosened up a bit. If that's never how it works, then never mind.

Using your logic what makes you think that there isn't any possibility that a never chambered round won’t set the bullet back on the initial chambering "unless you can measure it while it is in the chamber" (Your words)? Please...

Actually, yes I think that there is always a chance that a bullet could be set back on the very first chambering--it just seems a lot less likely than if the round had been stressed a number of times by repeated chambering. There are a number of other reasons why a round could blow up your gun when you did nothing wrong, as I'm sure you know, and these are risks that are inherent to shooting firearms. Maybe I'm a bit overzealous by some standards about mitigating risks that can be mitigated, but I see little reason to tempt fate and I'll take what I can get.

In the realm of "anything is possible" it might behoove you, for the sake of safety, never to use an auto-loader.

The thought has crossed my mind, actually, as well as the unlikely but possible jam right when I need my gun the most. Even less likely things have happened to me before, after all. But I still use autos because like everything else in life they are a calculated risk that I happen to be willing to take, currently. In the meantime, I'll continue to wear a seatbelt in my car even though I haven't needed one for the past 32 years or so, knock on wood.

Anyone remember the "medium load" blowups? Supposedly, a light to medium load in a rifle could cause some kind of high pressure "wave effect" and blow up the rifle.

I don't know about that, but I am aware that light loads using some very fast, energy-dense propellants can potentially--under some very specific conditions--result in detonation.

Now what about if your release the slide by hand in a controlled manor (ie:not letting it slam) compared to just dropping the slide via hand or slide release without control. Difference to ammo?

I suggested this earlier, and I think it would help extend the "chamberability" of a round.

 

[Shadow 7D]

Um, it's not the medium loads, the light (as in VERY light) 'no recoil' loads, basically there isn't enough powder to slow the combustion or something, and it all goes up before the bullet can move.

 

[Drail]

If the round is so poorly assembled that one chambering causes enough bullet setback to raise pressures then that round was a piece of junk before it ever came out of the box. I am so glad I took up reloading 25 years ago.

 

[Shadow 7D]

Most of the worst KABOOMs are from reloaders way UNDERLOADING a round.
some are from factory. The weird underloading pressure spike is completely a reloaders problem.

 

[NoAlibi]

Manco: "Maybe I'm a bit overzealous by some standards about mitigating risks that can be mitigated..."

That thought crossed my mind as well!

Manco: "The thought has crossed my mind, actually, as well as the unlikely but possible jam right when I need my gun the most. (Re: In the realm of "anything is possible" it might behoove you, for the sake of safety, never to use an auto-loader.)

Gotcha! You are aware that recoil can cause a bullet to back out of the case and then prevent the revolver's cylinder from rotating thus rendering it inoperable? What I had in mind for you was perhaps a single shot pistol like a Contender.

 

[Manco]

Gotcha! You are aware that recoil can cause a bullet to back out of the case and then prevent the revolver's cylinder from rotating thus rendering it inoperable?

Sure I'm aware of that, but I consider it less of a risk than jamming, even though my current defensive pistol has yet to jam on me after thousands of rounds. I'm sure that it will someday, though. It's all matter of assessing and comparing various risks, and deciding which are worthwhile and acceptable, relatively speaking.

Whenever a certain risk can be practically (albeit never completely) eliminated, I take advantage of such opportunities, as long as it is practical to do so. In the case of bullet setback, it costs me absolutely nothing to almost entirely eliminate this risk (defective cartridges notwithstanding), as I always like to shoot a few of my personal defense rounds every so often anyway. I don't find this overzealous in the least, although I'm sure that some folks would think that it is.

Also, I never suggested that you find a way to measure the length of a cartridge while it is inside the chamber--my point was that it is not practical, and I questioned whether measuring cartridges before they are rechambered could always give enough of a warning that a bullet could be set back enough next time to be a danger. For me it is easier and safer just to chamber each personal defense cartridge no more than once (or twice when I shoot it later).

What I had in mind for you was perhaps a single shot pistol like a Contender.

Where in my last post did I say anything about revolvers?

I believe it was the fine print on the back of a box of Speer Gold Dots I read, which stated the ammo was designed to withstand 4 chamberings. That seemed very specific to me.

That's all the more reason to limit the number of chamberings. They're probably being conservative, as I am, but then again maybe some individual cartridges really can't take more than that.

So I took out the calipers and started racking in rounds. Of the few I tested, it was like clockwork. The OAL was the same, same, same, same.... then it started to measurably shorten on the 5th or 6th chambering.

Just like I figured, the bullet needs to get loosened up before it starts moving. The question is whether it could move enough in a single chambering to become dangerous, and while that seems unlikely, in general by chambering the same cartridge repeatedly, one opens up more possibilities for failure. I'd rather just avoid the issue altogether--one less thing to think about and make excuses for in case something bad does happen, however unlikely (but...but...I measured it before I rechambered it for the 30th time--why me?! ).

 

[Thorgrim]

Shadow_7D wrote: Most of the worst KABOOMs are from reloaders way UNDERLOADING a round.
some are from factory. The weird underloading pressure spike is completely a reloaders problem.

Yep. That's one of the reasons I would never load a physically dense and powerful powder like Bullseye (the other reason being that it would be far too easy to miss an accidental double-charge during reloading).

The easiest insurance against set-back it to buy a canneluring tool and use it on the finished rounds.

 

[WardenWolf]

This is a problem fairly specific to the .40 caliber round that a lot of police departments currently favor. The .40 S&W, for whatever reason, is especially prone to bullet setback. This has never seemed to be an issue with the 9mm and .45 Glocks. But the Glock's unsupported chamber coupled with the bullet setback issue are a bad combination. Many police departments also use remanufactured ammunition to practice with, further exacerbating this problem.

 

[1SOW]

From the OP: "Sigarms Inc's personnel confirm that reloading the same round five or six times will cause the problems..."

I don't remember seeing a specific caliber, but the Sig 357 is necked down and has been cited as prone to bullet setback. Unlike a tapered 9mm the Sig 357 has a relatively small crimp area.

The reloading pages of M.D. Smith address this specific issue.

It would seem logical that tight chambered guns might be more prone to do this. The Glock is not famous for being tight chambered.

 

[NoAlibi]

Manco: "Where in my last post did I say anything about revolvers?

Given your proclivity for worst-case scenarios, with even the slightest chance of multiple assailants, a revolver seemed a natural choice for you. I now see that I didn’t go far enough - perhaps several single shot pistols secreted on your person for “New York reloads” would be the way to go.

Look, the fact that we drop the hammer on miniature pipe bombs in front of our faces puts all of us at some risk. I believe that a procedure whereby rounds chambered in a semi-auto, ejected and then checked for correct COAL greatly reduces the chance of a serious bullet set back on the next chambering - a risk I'm willing to take. If you think that discarding is the only way to go, then have at it. YMMV.....Doc

 

[Shadow 7D]

OR, you shoot a round like lil' 'ol .25 or .32 that are COMPRESSED loads...
sorry but, I haven't experience set back with my .32

 

[Skylerbone]

Seems we've gotten off the topic which is all Glocks explode all the tim...wait... NEVER MIND.

By the by those 200gr. SWCs were being chambered in a Citadel 1911, not a match chamber by any standard. I've seen some great photos of a revolver kaboom that IIRC happened on the third round. Sans proper crimping the preceeding shots loosened the bullets in the remaining rounds and the result was a 4 bullet volley. Unfortunately only 1 could be aligned with the barrel at the time which left the remaining 3 to shatter the frame in spectacular fashion.

Why are we arguing about this again? Setback does happen, it's good to be informed of such and even better to be diligent about it. Nit picking one man's threshold for safety is not much part of the arguement. We may as well have been asked how many rounds for break-in or, even better, what's the best lubricant for a "gun".

Here's to all of us staying safe and having enough self-control not to criticize another's habbit when said habbit errs on the side of safety. FWIW, I load my own SD rounds and generally keep 400-500 rounds in each caliber loaded which means shooting a few now and again (or 200 in a day) is the price of being prepared.

 

[Manco]

Given your proclivity for worst-case scenarios,

I think it is wise for ALL gun owners to consider what could happen in the worst case for many possibilities, given the typical severity of the consequences, whether or not they end up doing anything about it individually. I would suggest not chambering the same cartridge more than once or twice in a semiautomatic handgun just like I would suggest that people wear their seatbelts while in a vehicle, and prepare a will or living trust in case they die unexpectedly for any reason.

I may even suggest--please have a seat before I reveal the most startling worst case scenario of all--that people learn how to use a gun (despite the associated risks) to defend themselves! And just like that, most of the people of the world now consider me a paranoid nutcase for thinking that I need anything more than a cell phone to call the cops (to poke around my dead body--another worst case scenario), but it makes sense to me.

with even the slightest chance of multiple assailants,

Multiple assailants are the common case with home invasions, by the way.

a revolver seemed a natural choice for you. I now see that I didn’t go far enough - perhaps several single shot pistols secreted on your person for “New York reloads” would be the way to go.

Aside from home invasions, many real life defensive scenarios utilizing firearms do not involve any shots being fired at all, and I think that a single shot would suffice for the majority of other scenarios. Maybe you should switch to a revolver so that you won't have to break out the calipers every time you unload ...unless you're more worried about bullets backing out due to recoil, that is.

 

[Manco]

This is a problem fairly specific to the .40 caliber round that a lot of police departments currently favor. The .40 S&W, for whatever reason, is especially prone to bullet setback.

I think that .40 S&W is more prone to blowing up guns when bullets do get set back, due to its relatively high pressure and short, wide case, but I don't see a reason to believe that it is especially prone to bullet setback per se. I think that .357 SIG is probably more prone to the latter because of its short neck.

As for why we keep hearing about .40 S&W blowing up guns, I think that bullet setback is only one of several reasons this happens more frequently than we might expect, the design of the caliber being only one factor. I won't go any deeper into this issue here, but let's just say that .40 S&W cartridges prefer to have full support from the chamber...just sayin'....

This has never seemed to be an issue with the 9mm and .45 Glocks.

Check out the chamber support they've enjoyed all along (and the nearly full support that current .40 S&W Glock barrels provide). And of course, they're both less likely to kaboom to begin with, although it does happen.

 

[armyfazer]

@ Mainsail, the OP was about duty weapons. Duty weapons are routinely loaded and unloaded. Just imagine how many times we load and clear our weapons in the Sandbox!

Leave the wire; go hot. Return; clear your weapon. Repeat for a year!

 

[Mainsail]

^^^Ah, I didn't realize. We had to do the same if we had an RON. Stop at the base armory on the way to billeting, unload, turn in the gun and ammo, get a hand receipt. The next morning, reverse. Repeat for 20 years...retire.

 

[Drail]

Some ammunition will set back upon multiple chambering. I call that "defective ammo". It's not a "gun" problem and has nothing to do with caliber or how you work the slide. It is ammo made with no regard to precise tolerances. Loading your own will solve that problem simply because you care about your hands and the ammo companies do not.

 

[kk0g]

.......I hate it when people constantly just drop thier slide day after day. Puts to much wear on the gun for no reason IMHO.

Uhm maybe you're not aware but the slide drops forward every time you fire a pistol until you reach slide lock....... they're sort of designed that way.

 

[Sam1911]

Some ammunition will set back upon multiple chambering. I call that "defective ammo". It's not a "gun" problem and has nothing to do with caliber or how you work the slide. It is ammo made with no regard to precise tolerances. Loading your own will solve that problem simply because you care about your hands and the ammo companies do not.

I think it may be worth some kind of a test, but I doubt poor ammo quality really has all that much to do with it. I've had it happen with Hornady TAP rounds, and they're pretty decent quality.

Take any round of any handgun ammo made, and chamber that round repeatedly. Measure after each chambering. Pretty simple test, really. I'd bet after 10, and certainly by 20, chamberings you're going to see a bit of set-back.

I can't carry every day (I work in MD) and I don't leave my carry guns loaded while I'm away because of inquisitive children (though they've never once touched a gun when not allowed) so my ammo gets loaded and unloaded regularly. I try to rotate the ammo in my carry mags so no one round gets chambered every time, and then do shoot up my carry rounds every once in a while and buy fresh. Even so, I've seen very good quality ammo "set-back."

 

[PapaG]

Thanks for posting this one guys. I brought this up on another site after finding my .380 round telescoped into the case a good quarter inch...after probably a dozen chamberings in my LCP. I suggested to those folks that they should check rounds that have been repeatedly chambered and then reinserted into the magazine. What a pile of putdowns I got.
They I sent in pix of the grips, damaged magazine, and blown case from my old 39 Smith that had telescoped a round into the case (first chambering but somehow I had loaded some thinwall brass...since sorted out and destroyed). The castigations on my honor stopped.
'Course, these are the same people who don't think anything of recommending you go ahead and shoot up powder that got mixed by accident, loading over the manual recommendations (heck, dummy, them manufacturers build 'em to hold double proof loads).
Thanks again. Glad to see rational folks sharing safety tips.

 

[railroader]

This why I like my ruger p95. The manual states it is fine to lock the slide back, drop a round in the chamber then release the slide release. No bullet setback. Other ruger p series pistols are the same way. I don't do this with my other pistols by the way.