New Style Bullet

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Ok:in the past two years I have been reloading 9mm ammo with 124grn Rem FMJ never a problem at MOL 1,150.Today I switched to Hornady 124grn fmjfp at 1.150.Failure to chamber completely.Solved problem by setting bullet to 1.144.Will the extra depth affect pressures in a bad way.I am loading Red Dot at 3/10's below max for this combination.
 
I wouldn't worry about a change of only .006 in length. Especially with a reduced load and loading that far out to begin with. I was experimenting with much shorter loads trying to get a SIG P6 to work. Loaded down to 1.020 and started seeing signs of pressure even with starting loads.
 
Here's what Speer has to say about OAL and the 9mm. Speer took a load that when seated to it's SAAMI established depth was producing 28,000, CUP was the pressure measurement table back then. So the Speer ballistic experts seated the bullet in that same load to .030" deeper and the nromal 28,000 jumped to an alarming 63,000.

So in response to your question, considering you are already loading near the top with a fast burning powder, it would be wise to reduce your powder charge and re-work the load, carefully.

Considering you are shooting a jacketed bullet, is there any particular reason why you are using such a fast burning powder, especially with the heavier 115 gr. and 124 gr. bullets? It must be a constant task to maintain reasonable pressures @ 1,150 fps?

Have you ever tried loading with slower burning powders like HS6 or Longshot, just to name two very good performer's. The reason I mentioned this is, there are numerous better powder choices for high velocity loads, such as your's, than Red Dot. I load a 124 gr. XTP with Longshot, my loads chronograph at 1300 fps and some change and I'm still at about mid range. The 115 gr. XTP is hitting 1400 fps with HS6.
 
With the deeper seat/shorter oal, Reduce the load and start over as if it's a new load.
A chrono would help.
 
Plugged this into Quickload, guessing on what charge you were using. Got this for the pressure difference:

1.150 27397
1.144 27986
 
Trip to the range today.

So I went to the range today with a hundred 9mm reloads of Remington FMJ.
They ran through my 3913 without a hitch.Then came three reloads of the new bullet,1rnd no problem,2nd rnd problem,slide did not go to battery,1/4" shy.Could not extract jammed bullet.When I returned home I put the gun into my carpenters vise with the nylon jaws.Being very careful I slowley closed it onto the front of the slide and the part of the grip that sits into the hand between the thumb and trigger finger.Slight pressure and slide was free.After remoning the stuck case.I smoke treated the bullet/after removing the powder.Re inserted the bullet into barrel only.There wes a ring on the ogive about 0.025.Bullet was hard to remove again pushed out with dowel.After a few tries at dirrerent depths I established that the only depth that would not stick would be too dangerous to atempt,it would have to be 1.125, That is a diference of 0.019.I will try to call Hornady monday for some help.:confused:
 
There is nothing wrong with loading a 9mm at 1.125 with a 125 grain bullet. If you are worried, just reduce the load by a few tenths and work back up until the gun cycles again. Of course watch for signs of pressure while you are doing this.
 
IMHO you are playing with fire, sir. Let me tell you why I believe this...

► First off, Red Dot is not A fast powder, it just happens to be one of THE fastest powders. Out of 270 listed powders on THIS LIST it is #10. That should set off flashing red lights and sirens in your head.

Ever see a photo of a blown up gun? Probably 85% of the time that's done with "fast" powders, and the reason is that with "fast" powders things that can go wrong go wildly wrong much, much faster. So right off you're walking a razor's edge with Red Dot.

Nothing wrong with Red Dot mind you. Many people use it. Just a standard safety warning.

► You have run into the rather standard problem of the shoulder of the bullet striking the rifling on your 9mm. Happens all the time as you can see in the cartoon below....

Bullet%252520Shapes.jpg

You have determined a new OAL that allows the receiver to close. That's good, but may not be good enough. IMHO it's not enough to know you clear, you really need to know by how much you clear. It's the same as if you were lost in a downtown area and figuring out you are not in Miami. That still doesn't answer the real question of where you actually are.

The reason is that you never want the bullet to be touching the rifling. The bullet must have time to start moving before it engages the rifling. If the bullet is resting on the rifling at the time of powder ignition, then you get a pressure spike because the bullet is having a very hard time simply getting moving. You'd have the same issue if you nudged your car's wheels up against a curb and then 'gassed it' trying to jump the curb. It's simply much easier to get a 'running start' at the curb.

The root of the problem is that all reloading presses produce ammo with varying OALs. Let's pretend that your new OAL of 1.144" just clears the rifling by .002", but your press and reloading technique produce ammo that has a tolerance of +.007" and -.004". When you aim to make ammo that is 1.144" you actually produce ammo that measures anywhere from 1.151" to 1.140". Obviously the ammo made at 1.146" to 1.151" is hitting the rifling and probably inducing the dreaded pressure spike.

Summation
When you combine probability of higher pressures with the probability of a bullet buried in the rifling it's no longer called reloading, it's called gambling. I highly suggest you take these steps:
• Hopefully use a somewhat slower powder in the speed range of Win 231 to Win WSF
• Find out at what OAL the bullet touches the rifling and then reduce the OAL by an additional .010"
• Find a published load for 124gr jacketed at (or below) that new reduced OAL and begin again at the "starting load" and work up slowly

Hope this helps! ;)
 
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You might have noticed the Hornady bullets are shaped completely different then the Rem FMJ-RN?

As such, you cannot use the same OAL with them because there is more full dia bullet sticking out of the case at the same length as a RN..

1.090" would be a pretty normal operating OAL with Hornady 115's to miss the rifling leade in a lot of guns.

Don't worry about it, but reduce the charge & start over working back up.

rc
 
+1 on RC

My reloading notes say that in May of 2008 I loaded these same bullets for a CZ SP-01 and my measurements showed the MAXIMUM permissible OAL was 1.090".

Max OAL is going to vary by gun. The combination of bullet and barrel determine the MAX OAL.

Your mileage may vary.
 
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I agree with the 'warning' replys. the only advantage RDot offers jacketed bullet loaders is it's a low-flash powder. I use it with great results with well-lubed cast slugs though. for loadings from .32acp - .45acp.
 
After reading all the helpful replies, and knowing that I had a problem before my posting,I knew that I would be pulling the loads that I had already made.
I will be puting some time on my inerta bullet puller,and changing the powder type also.When all is done and tested I will let all know how things worked out.Thanks to all who replied.
 
if you want a good idea of what your working toward I will tell you a little story.. this month last year I was shooting my sig p226 .40 loaded with tightgroup.. a fairly fast powder and small charge. the particular charge i was using was very safe... however going much hotter than that and pressures spiked a lot..i made a mistake somewhere... I ruptured a cased and the friendly surgeons at the local hospital kindly removed it from my right eye(my shooting eye) after a year, and a little grace from the man upstairs I'm at 20/20 vision...IT'S NOT WORTH IT! get the proper powder for seating at those depths,, I could buy 6 new sigs for what that surgery cost, and yes I wasn't wearing glasses, but glasses only protect eyes, a piece of your slide goes through your cheek and it it won't be worth it... I'm sure your an experienced loader but all I can tell you is I have changed very much what I consider a "good idea"... I do hope you get it all worked out though
 
I'm back,spoke to customer service at Hornady today.The rep gave me a MOL using Unique of 1.050 4.0 starting/5 max.I am going to load ten rounds at , one tenth increments,I'll keep in touch.
 
Finally!

Took my new reloads to the range and shot them all without any problems.Only had 50 rounds of 9mm 124FMJFP.Ten rounds of each Starting at 4.0 Unique to 4.4.MOL 1.075,no harsh recoil,flat primers but no cratering.All shots into a 3'' target at 10yds.I'll load them at 4.3 and be happy with the results.
 
Glad to see you got things sorted out. In addition to the others' input, I was going to add that 1.15 seems really long for a 124gr bullet. The longest 9mm I load is a 147gr Bear Creek FPTC at 1.13.

For future reference when working up a load, take your pistol barrel and drop a loaded round into it. It should "plunk" and the base of the case should be flush or slightly below the breech face. Turn it over and the round should fall out freely. This tells you that the bullet is not jamming into the rifling.
 
.40 loaded with tightgroup.. a fairly fast powder and small charge. the particular charge i was using was very safe... however going much hotter than that and pressures spiked a lot..i made a mistake somewhere...
Click to expand...

.40 S&W + Tightgroup.:uhoh: Yours is not an uncommon story. I'm glad that yours ended not as badly as it might have.
Even with Bullseye & Green Dot in 9mm I've found some pretty small changes in OALor charge weight can affect accuracy noticably.
After loading loads of .45ACP & .38/.357 Magnums I'm fairly new to 9mm & have developed a pretty healthy respect for the high pressure rounds. Doesn't take much error to screw the pooch.
 
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