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Posted: 10/22/2006 7:46:58 AM EST
[Last Edit: 11/1/2006 4:28:05 PM EST by lu380]
I have had a lot of bullet set-back problems with Cor-Bon over the years. I recently bought a Bersa .380 and all they had available at that gun shop was Cor Bon, so I reluctantly bought a box.

After examining the chambered round (which was only chambered once), I noticed that it was noticeably shorter than the other rounds in the mag. I'm talking about 2mm, not a couple of thousandths. Another thing I noticed about Cor Bon is that the cases seem to dent a lot easier than other rounds from different manufacturers. By simply loading them into a mag, they have enormous dents behind the crimp.

Am I the only one to notice this?
Link Posted: 10/22/2006 7:55:13 AM EST
I've fired CorBon in 45ACP and 40S&W.

both were the std. Corbon high velocity rounds (not DPX)

I haven't had any problems yet, but I'll be on the lookout.

thanks for the heads up.
Link Posted: 10/22/2006 8:35:27 AM EST
I've had the same problem consistently, regardless of which flavor of ammo they produce. I'm 100% sure there's a problem in the way they crimp their ammo.
Link Posted: 10/23/2006 2:54:16 PM EST
I've chambered the same two rounds of 9mm DPX (alternating) over a hundred times. They still look new except for tarnish.
Link Posted: 10/23/2006 6:36:51 PM EST
If you have problems with the ammo, I would recommend contacting Corbon and sending it in along with the box - at the very least you might get some free ammo that SHOULD work
Link Posted: 10/23/2006 7:11:08 PM EST

Originally Posted By P229SAS:
If you have problems with the ammo, I would recommend contacting Corbon and sending it in along with the box - at the very least you might get some free ammo that SHOULD work


I have had this same problem with Cor Bon over several years, with several different firearms, and several calibers - consistently. I'm 100% certain there is a problem with the crimping process and/or the brass they use.
Link Posted: 10/28/2006 12:27:26 AM EST
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Originally Posted By Schulze:
I've chambered the same two rounds of 9mm DPX (alternating) over a hundred times. They still look new except for tarnish.


Me too.

The DPX 9mm does not seem to have any problems with setback, at least not in my XD-9.

I used to carry Corbon 115gr +P JHP in my Beretta 92F Compact before the DPX came out. No problems with setback on those either.

I had some Winchester 115gr Silver Tips that had big setback problems in my Beretta.

Link Posted: 10/28/2006 8:54:33 PM EST

Originally Posted By DamonMonWai:

I had some Winchester 115gr Silver Tips that had big setback problems in my Beretta.



Silvertips are also a problem in my experience. Not so much set-back, but deformed bullets because they're so soft.
Link Posted: 10/30/2006 3:54:06 AM EST
Never had a problem with Corbon.
Link Posted: 10/30/2006 4:16:53 AM EST
[Last Edit: 10/30/2006 4:20:31 AM EST by markm]
First off... I've never heard of a "Crimp" on Auto pistol ammo. I mean.. they crimp some .357 magnum into the cannalure, but that's all together different.

And have you eliminated the possibility that the "Bersa" or whatever pistol is the problem? I mean I could be that this Saturday night special of yours has a rough feed ramp or something that the hollow points are impacting.

For example, I have had set back problems with 1911s on all kinds of ammo, including ball. But the problem is less evident on modern autoloaders like glock. They feed more directly into the chamber.

If there were a problem with the ammo, I'd guess that It would be common knowledge on this site.
Link Posted: 10/30/2006 5:43:24 AM EST
"First off... I've never heard of a "Crimp" on Auto pistol ammo."

Better keep listening.
.45 ACP ammo (and other auto pistol ammo that headspaces on the mouth) receives a taper crimp to remove belling needed to seat the bullet.
Ammunition for full auto use is also often crimped more aggressively in a manner that leaves a portion of the mouth for headspacing but further increases the force required to push the bullet back into the case.
There are a number of styles for this crimp, but a relatively common one leaves three areas of about 90 degrees crimped tightly, and three areas of about 30 degrees for headspacing.
Link Posted: 10/30/2006 5:50:32 AM EST

Originally Posted By brickeyee:
.45 ACP ammo (and other auto pistol ammo that headspaces on the mouth) receives a taper crimp to remove belling needed to seat the bullet.


You just made my point exactly. The "crimp" on autoloading ammo is to straighten out the case wall.

My Dillon instructions SPECIFICALLY state that the "crimp" is to remove belling, and not for the purpose of holding the bullet in place.
Link Posted: 10/31/2006 4:04:59 PM EST

Originally Posted By markm:
First off... I've never heard of a "Crimp" on Auto pistol ammo. I mean.. they crimp some .357 magnum into the cannalure, but that's all together different.

And have you eliminated the possibility that the "Bersa" or whatever pistol is the problem? I mean I could be that this Saturday night special of yours has a rough feed ramp or something that the hollow points are impacting.

For example, I have had set back problems with 1911s on all kinds of ammo, including ball. But the problem is less evident on modern autoloaders like glock. They feed more directly into the chamber.

If there were a problem with the ammo, I'd guess that It would be common knowledge on this site.


Yes, I'm aware of the fact that autoloader ammo is not roll-crimped. It's the sizing of the case walls that holds the bullet in place, while the taper-crimp is simply to squeeze the flared case mouth back where it belongs after bullet seating. I believe that Cor-Bon does not squeeze the case wall in far enough when sizing their brass to hold the bullet with enough tension to hold the bullet in place securely. Either that, or the brass is thinner than other brands around the case neck area.

Admittedly, the one round that was VERY noticeably set back is one that slammed into the bottom of the feed ramp during a sloppy hand-cycle. I still think that even under these circumstances, the bullet would have stayed put better than it did if it were Ranger SXT's.

I also have had similar experiences with 1911's vs. modern autopistols with bullet set back.
Link Posted: 11/1/2006 12:30:48 PM EST
lu380,

We do put a slight taper crimp on our auto pistol ammo. We also cannelure our brass for all of our auto pistol ammo to help keep the bullet set back problem from happening. We were the first or at least one of the first manufacturers to use a cannelure on the brass. The cannelure is set up for each individual bullet for seating. It's possible that there was a soft lot of brass, but we do check brass hardness in our R&D process.

Some of our DPX auto pistol ammo does not have a cannelure due to the length of the bullet. They are seating in the area where the brass gets thicker near the case head.

If you have some of that lot left, please return it to us and we'll examine it and replace it 2 for 1 for you.
Link Posted: 11/1/2006 4:26:11 PM EST

Originally Posted By TeamCorbon:
lu380,

We do put a slight taper crimp on our auto pistol ammo. We also cannelure our brass for all of our auto pistol ammo to help keep the bullet set back problem from happening. We were the first or at least one of the first manufacturers to use a cannelure on the brass. The cannelure is set up for each individual bullet for seating. It's possible that there was a soft lot of brass, but we do check brass hardness in our R&D process.

Some of our DPX auto pistol ammo does not have a cannelure due to the length of the bullet. They are seating in the area where the brass gets thicker near the case head.

If you have some of that lot left, please return it to us and we'll examine it and replace it 2 for 1 for you.


Thank you for the generous offer, but I'm far too lazy to actually do anything more than complain over the internet. J/K PM me your address and I'll send it out over the weekend.

My apologies for calling the ammo junk, but this has been a consistent problem for me over many years.

I'm convinced that slight improvements could be made to fix it and I'll give you some specifics that I've noticed:

*In 9mm, the 90-grain loads have the worst setback problems for me. This could be due to the shorter overall length combined with the sharply truncated shape and sharp edge at the mouth of the bullets.


*The load that set back in my Bersa was a .380 with a 90-grain bullet

*The cannelure in the brass seems to be pressed in much deeper than [for instance] Federal's Hydra-Shok ammo. I think that this might actually cause the case to lose tension in the neck area by flaring it out as the cannelure area gets pressed in. (Did that make any sense?)
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