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Said waaaat.... 357Sig Glock blow-ups due to a heavy crimp?

6K views 64 replies 22 participants last post by  Taterhead 
#1 ·
Recently a guy on another websight suggested that a top load 357Sig reload can blow up a Glock if the crimp is applied too strong. All he offered for the comment was "Ask me how I know this." While I do know that the 357Sig is loaded to higher SAAMI pressures then many other of the usual auto pistol rounds, I have NEVER heard of ANY cartridge (rifle or pistol) blowing up a pistol solely due to over crimping the case. If a "blow-up" truly happened, I would presume the cause was more likely due to his reload going over the red line of the SAAMI limit to begin with.... and much less to do with an excess crimp on a round reloaded within SAAMI limits.

During 40 years, I personally have applied stout roll crimps onto all kinds of hot loaded handgun ammo including 44 mag and 10mm, and I find it hard to believe that a 357Sig is the exception. Anybody else heard of this with the 357Sig?
 
#4 ·
Can a heavily crimped .357 Sig round blow up? Yes. Was the heavy crimp the cause? Unlikely.

If he were running on the bleeding edge of maximum pressure any variable might have caused the problem.
 
#5 ·
If you throw a double charge you could crimp anyway you want and it can blow up a gun.

Over crimping can swage the bullet so the base is smaller diameter than it was, that is not going to raise pressure on its own.

Too little neck tension can cause bullet set back and can raise pressure dramatically. If you have a neck tension problem it is unlikely that you will solve it with further crimping.

Opposite bullet setback would be seating it far enough out that the bullet contacts the rifling as the round is chambered. That too can raise pressures.

I know the above from 30+ years of reloading. Another thing I have learned from being alive even longer than that is that people like to blame other things when they themselves make a mistake.

Ask me how I know this.
 
#6 ·
Ah no, on the crimp.

Too much of too fast a powder, pretty sure that will do it.

Never discount bullet setback with a cartridge like 357 SIG, especially when running way below 100% load density.

Totally agree on jmorris' assessment of people and their rationalizations. Some of the most extravagant myths ever devised by man exist in the world of reloading, all for the ego's of those that just can't admit they used too much of too fast a powder or they loaded a squib and never checked the bore before firing a non-squib. :)
 
#8 ·
Not really. Fact, the opp is often the case. Too much crimp on The short 357sig neck is likely to cause loss of neck tension & reduced pressures. The same loss of case neck could cause a bullet setback. That is a far more serious issue with a max load, esoecially with the wrong powder. So could over crimping be an issue, maybe, but not for the reasons the op inferred.
 
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#9 · (Edited)
Ok guys....as I mentioned in my opening post, I doubted this myself but wanted to get a general consensus to feel better. Well..... with 7 of you saying that it's bunk, I can say that this is that good "consensus" that I was seeking!! :cheers: Thanks.

The fact that the 357Sig is loaded to about 5,000 PSI higher then say the 40S&W, and the factory Glock barrel does not fully encase the rim, gave me cause for concern. But, I've been saving the best for last: I crimp the living s*** out of my practice loads!!!! ....and so that was the main concern I had! Ya see, it goes like this; I got a good deal on a bunch of Remington round nose 9mm 124JHP bullets from Midway when I first bought the GL33 pistol and and I didn't realize that the Ogive radius on the 9mm Rem bullet would be too long for a 357Sig cartridge when the bullet is seated at the proper OAL length. Part of the bullet radius ends up right at the case mouth, and so there isn't enough brass on the narrow little case neck to firmly grip the bullet. I have therefore resorted to crimping the case mouth VERY tight so that it locks onto the ogive of the bullet. (I keep detailed notes of my crimp die setting for consistent reloads and performance) The bullet no longer slides into the case like when it use to during the onset of my exploring the round. FYI; I settled on 9.4gr BlueDot which provides very good accuracy and similar recoil as my Speer GoldDot factory loads for duplicate range practice. I had also tried 9.8gr which needlessly recoiled too much. BTW, I do use a LoneWolf barrel which also encases the case rim better, and Speer brass which has stronger webbing. I use a heavier recoil spring too. I read my fired case heads/primers for signs of flattening, and keep the flatness less then what my fired Speer Factory cartridge heads/primers show. I expect to hear a naysayer along the way (there's always one LOL), but my Glock 33 spins like a top and hasn't malfunctioned once!
 
#10 ·
Take one of your loaded rounds and measure your COL. Then using your bathroom scale. Press the nose of the bullet into the center of the scale until it reads 40Lbs. Then measure the round again. If you have setback you are over crimping. Over crimping a taper crimp does not grip the round tighter just the opposite.You can also over crimp where the bullet will fall out of the loaded case.
 
#14 ·
I didn't know that. Thanks!
 
#11 · (Edited)
Can a heavily crimped .357 Sig round blow up? Yes. Was the heavy crimp the cause? Unlikely.

If he were running on the bleeding edge of maximum pressure any variable might have caused the problem.
Absolutely. And in addition to higher working pressures and limited case capacity (compared to 357 Mag) seating depth is extremely critical because with some bullets, to seat the bullet to the correct OAL so the cartridge will feed may result in seating the bullet too deep and boosting the pressures way beyond maximum. And that is the one other variable that most likely caused the problem and not the crimp, and I think that we'll be hearing more and more of "ka-booms" with the 357 sig as more people start reloading it.

It's important to use load data that gives a powder charge for a specific bullet at a specific OAL and you cannot mix & match or do guesswork. There are bullets designed specifically for the 357 sig and using bullets designed for the 9mm can get you into big trouble. The 357 Sig is not a good cartridge for beginners to start reloading. The same is true of the 460 Rowland. If you reload either of these two cartridges, do so with great care and never start with a maximum load. And always use published data and the absolute best source for load data is one of the Loadbooks USA manuals.

Always work up to maximum gradually. I always start at about 8 tenths of a grain below max and work up by two tenths of a grain and I mark my primers with different colored sharpies and keep note and make notes on the targets. I also have a bullet puller and will not shoot the max loads if the other loads seem too hot. And with the 357 Sig, do not obsess over high velocity.

If your reloads are not giving you high enough velocities, buy Underwood, Double tap or Buffalo Bore ammo for your carry loads. They use pressure testing equipment to develop their max loads. I've been reloading since 1968 starting with a Lee Loader that cost about seven dollars at the time.
 
#13 ·
No reloaded ammo can or will blow up because of a heavy crimp. Ask me how I know this. Now link this in a reply on his post.
Agree completely. No way that a crimp affects pressure on any level that is dangerous. There is some dumb stuff that can, that just isn't one of them.
 
#15 ·
With most crimp dies for the .357sig if you apply too much crimp you will crush the shoulder of the case enough that the round will not chamber. The Lee collet crimp FCD for the .357sig won't crush the case but too much crimp actually pulls the neck rearward of the crimp outward which can cause some loss of neck tension. The guy likely made an error in his powder charge.
 
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#19 ·
Yep..... A LEE factory Crimp Die is what I use.I look for an outside case neck diameter of .373-375" with .378 being the widest diameter. I periodically check all my reloads in my Wilson headspace gage too.
If you'll notice in my opening post, I didn't think a crimp should ever cause a blowup, and just wanted to verify that about the 357Sig too....... mainly because of the higher pressures and less barrel reinforcement at the case rim. But, I suppose if that was a valid factor, I'd have already experienced a kaboom during my 200 high pressure reloads and this thread wouldn't have been possible to type with only 3 fingers left.:ack:
 
#16 · (Edited)
Over crimping is not a good solution to improper bullet choice. Still, guys have been roll crimping the 357sig since the beginning. Next bullet choice, truncated cone only for bullets over 115gr.
 
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#18 · (Edited)
Over crimping is not a good solutionto improper bullet choice. Still, guys have been roll crimping the 357sig since the beginning. Next bullet choice, truncated cone only for bullets over 115gr.
No, I'm not "roll crimping an improper bullet choice". Instead, I'm using a "Lee Factory Crimp" Die to put that crimp on my improper bullet choice. :supergrin: What I'm doing with the improper 9mm Rem124JHP bullet works reliably and accurately, and I'll continue to blow through the 100 or so rounds of it at the range for practice until it's gone.

IF ANYBODY CARES TO KNOW WHAT LOADS HAVE WORKED WELL FOR ME;

My preferred bullets of choice for reloads range practice is the Hornady 124XTP with 7.9gr of Unique, and cci500, which is a quality inexpensive bullet that has great bearing surface for a firm neck grip, but is not expensive to use. The best simulation practice bullet that I reload is the Speer 125 GoldDot, which is a perfect simulation of the factory cartridge I carry, but unfortunately a very expensive bullet to shoot randomly for practice. With a 4" Lone Wolf barrel, I'm actually getting 1420FPS with 8.8gr of PowerPistol powder and a cci500, while the factory cartridge with the same 125gold dot bullet gives me only 1320fps!! With 7.8gr of Unique powder, cci500, and the 125GoldDot, I get the same recoil and feel as the factory cartridge for inexpensive, realistic practice (compared to the factory cartridge), but with less primer flattening to boot. Accuracy with both the XTP and the GoldDot bullets is excellent. The Remington 9mm 124JHP shoots very accurately too, but is improper to use in this cartridge due to the long ogive. The 357Sig is an accurate gun no doubt. I use a stronger 20lb replacement recoil spring/rod for these heavier loads.
 
#20 · (Edited)
He had a problem and blamed it on what HE thought the problem was. I have never seen a crimp be a problem. The .357 Sig is not a overly high-pressure cartridge, but a charge error is always a possibilty. The neck is very short and he may have had severe bullet set-back despite an over-crimp in his mind.
He also may have simply started at or near the max load and it was over-max for his gun and his components.
The .40 S&W was rushed into production and has less web than a 9x19 cartridge and suffers KBs a lot easier than any other cartridge. The .357 Sig does NOT use the .40 S&W case as the base, other than geometry, and, reportedly, has a good thick web.

Sporting Arms and Ammunition Manufacturers' Institute
Handgun Max, psi

9mm Luger 35,000
9mm Luger +P 38,500
38 Super Auto +P 36,500
357 Sig 40,000
357 Magnum 35,000
357 Remington Max 40,000
40 S&W 35,000
10mm Auto 37,500
41 Remington Mag 35,000
44 Remington Mag 36,000
454 Casull 65,000
480 Ruger 48,000
 
#21 ·
While Fred and I disagree about the use of the LFCD, I do agree with him that it can be, and many times is overdone and causes a bullet to "spin" in the case.

Even so, if you think about it and even though not meant to be used for excess crimp, it can't increase pressure to any dangerous degree. Given that the bearing surfaces for an igniting round are is the breech face and chamber, something has to give and even the most crimped bullet doesn't compare with either.
 
#22 ·
Recently a guy on another websight suggested that a top load 357Sig reload can blow up a Glock if the crimp is applied too strong. All he offered for the comment was "Ask me how I know this."
He may be confusing a rifle round with the 357Sig round because they are both bottleneck rounds. Lee talks about too long cases pinching the bullet in the chamber and causing excessive pressure. See the last bullet of the link.

http://www.leeprecision.com/cgi-data/instruct/SE3180.pdf
Trim length is not critical. However, be certain that your cases are no longer than specifications as a case excessively long will pinch the bullet in the end of your gun’s chamber and cause dangerous pressures. Cases trimmed excessively short cannot be crimped.​

In this case, the chamber is preventing a too long case from releasing the bullet. Obviously, this depends on the chamber profile. Probably more of an issue in bolt action, where the camming can really force a round into the chamber. There's a difference between an intended crimp and an unintended crimp.

I don't think it's a problem with 357Sig.
 
#23 ·
Here's a question that always bugged me about bullet setback and excessive pressure.

If the neck tension is not sufficient to retain a bullet; then you have the potential of setback. I think everyone can agree to that.

However, if there is insufficient neck tension to keep the bullet in place, then why would you have excessive pressure when the round is fired. Wouldn't the same insufficient neck tension that allowed the bullet to setback, would also allow the bullet to start moving at a lower pressure? As an excessive case, I found some loaded 45ACP at the range. The neck tension was so insufficient, that I could push the bullet flush with the case with finger pressure alone. Had I fired those rounds (I didn't), what was going to hold the pressure in, and lead to excessive pressure. I think a sneeze would have moved those bullets. It was as if the cases were not even sized.

OTOH, I can certainly see an over pressure problem with a bullet that was set too deep in a case with sufficient neck tension.

There's nothing good about insufficient neck tension. I can see it causing wide swings in velocity and long range accuracy. I'm just curious if it would result in a kaboom.
 
#26 ·
True, I have chambered many barrels, the single shot are
usually much better supported, Rug #1, TC, H&R are some
of the most supported, Freedom Arms in the revolvers are
some of the best.

Even when doing a 03 or P 17 I always get the barrel, chamber,
as close as possible to the bolt face, the more the case in that
barrel the better.
 
#25 ·
However, if there is insufficient neck tension to keep the bullet in place, then why would you have excessive pressure when the round is fired. Wouldn't the same insufficient neck tension that allowed the bullet to setback, would also allow the bullet to start moving at a lower pressure?
"Sufficient/insufficient" is use about the bullet moving before the primer is ignited, the crimp won't have a huge effect of pressures as long as the bullet doesn't move. Having a case too long is another story all together and can be a problem despite the use of a crimp or not.

Set back changes the internal volume of the round and in some cases (no pun intended) can be quite drastic.

Like this example from Speer #11.



.030" of set back increased the operating pressure 34,000 cup more than doubling, that could cause a KB.
 
#27 ·
Humm, not sure about this, that is over crimping reduces tension. I accidently over crimped some 9mm plated bullets due to a loose lock ring on a Lee factory crimp die. The die had moved down in the tool head. The rounds actually squirted the lead core out before the plating. The plating came out in shards that stuck in the target.
Brass when it goes into a sizing die is smaller than when it comes back out of the die to the right size. It's the same as bending sheet metal. You have to go past what you want because it will spring back. The case does the same thing, When you crimp the case when it comes back out of the die the brass springs back out some. Plated bullets are lead with a thin copper coating. Lead does not spring back like the brass if any at all. So if you over crimp, the case springs back out and the bullet says the same as when you just resized the bullet.So now you have not tightened the bullet in the case you just loosened it.
Now over crimping a copper plated bullet. If you break the copper coating on the bullet. You will get the lead and copper plating separation. That is why when you crimp plated bullet that you pull the bullet and check to make sure that there is no or a very light indentation of where the mouth of the case was.
A taper crimp is not a crimp at all. You are only removing the bell on the case that you put on the case so you can seat the bullet without shaving the plating.
 
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#28 ·
Here's a question that always bugged me about bullet setback and excessive pressure.

If the neck tension is not sufficient to retain a bullet; then you have the potential of setback. I think everyone can agree to that.

However, if there is insufficient neck tension to keep the bullet in place, then why would you have excessive pressure when the round is fired. Wouldn't the same insufficient neck tension that allowed the bullet to setback, would also allow the bullet to start moving at a lower pressure? As an excessive case, I found some loaded 45ACP at the range. The neck tension was so insufficient, that I could push the bullet flush with the case with finger pressure alone. Had I fired those rounds (I didn't), what was going to hold the pressure in, and lead to excessive pressure. I think a sneeze would have moved those bullets. It was as if the cases were not even sized.

OTOH, I can certainly see an over pressure problem with a bullet that was set too deep in a case with sufficient neck tension.

There's nothing good about insufficient neck tension. I can see it causing wide swings in velocity and long range accuracy. I'm just curious if it would result in a kaboom.
It is a balancing act. Some setback will raise pressures. Setback enough for total loss of neck tension, pressures drop a bit. A pressure chart has been posted by ATK shown bullet setback. I just can't find it.
 
#29 ·
While Fred and I disagree about the use of the LFCD, I do agree with him that it can be, and many times is overdone and causes a bullet to "spin" in the case.

Even so, if you think about it and even though not meant to be used for excess crimp, it can't increase pressure to any dangerous degree. Given that the bearing surfaces for an igniting round are is the breech face and chamber, something has to give and even the most crimped bullet doesn't compare with either.
But the LFCD for the 357sig is like the rifle one, so I really have no objection to it.
 
#30 ·
No, I'm not "roll crimping an improper bullet choice". Instead, I'm using a "Lee Factory Crimp" Die to put that crimp on my improper bullet choice. :supergrin: What I'm doing with the improper 9mm Rem124JHP bullet works reliably and accurately, and I'll continue to blow through the 100 or so rounds of it at the range for practice until it's gone.
.
WHile not a roll crimp, the LFCD for the 357sig is NOT a taper crimp, more like a roll crimp. Trying to use the crimp to hold the bullet in place is just a poor solution, all I am trying to point out.
 
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#33 ·
Here's a question that always bugged me about bullet setback and excessive pressure.

If the neck tension is not sufficient to retain a bullet; then you have the potential of setback. I think everyone can agree to that.

However, if there is insufficient neck tension to keep the bullet in place, then why would you have excessive pressure when the round is fired. Wouldn't the same insufficient neck tension that allowed the bullet to setback, would also allow the bullet to start moving at a lower pressure? ......
With a rifle cartridge, a "running start" of a bullet seated deeper in the case and further from the rifling will reduce pressure is what I have known my entire adult life of reloading ammo. This is also explained clearly at the beginning of every Hornady book. This seems to be reverse with pistols; A bullet set back in the case will increase pressure. Either way, I will continue to do what I have ALWAYS done, which is to reload pistol ammo to the designated OAL length specified in the bullet manufacturers spec sheet/ reloading book, and with pistol ammo also make sure the bullet is held firmly in place.
 
#36 ·
With a rifle cartridge, a "running start" of a bullet seated deeper in the case and further from the rifling will reduce pressure is what I have known my entire adult life of reloading ammo. This is also explained clearly at the beginning of every Hornady book. This seems to be reverse with pistols; A bullet set back in the case will increase pressure. Either way, I will continue to do what I have ALWAYS done, which is to reload pistol ammo to the designated OAL length specified in the bullet manufacturers spec sheet/ reloading book, and with pistol ammo also make sure the bullet is held firmly in place.
Mostly because the case capacity is small & the powder much much faster. THink the slowest pistol powder is the fastest rifle powder & the smaller rifle rds, like 223, have about 4x the case cap of a 9mm, you can see why setback is an issue. Of course you still don't want a bullet wedged into the rifling in a handgun either.
 
#35 ·
There are not a lot of firearms that do fully encase the rim. Most of the ones that I own that do are single shot break open style firearms.
You are right, but, it is said that part of the reason for a Glock's reliable operation is that the chamber is a bit loose by a few thousandths. I have never actually compared chambers of my LoneWolf barrel or a KKM barrel against the Glock OEM barrel, but I'm told that these after market barrel chambers are tighter and also provide more circumference of metal around the case head. This would be especially important with high pressure rounds like the Rowland. This is also reassuring to me when I'm firing a 357Sig 125GoldDot bullet out of my 4" barrel at 1420fps. (100FPS faster then the factory cartridge I've clocked)
 
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