Causes for weird bullet set back!

[FLBri]

I've never seen this before. Someone please enlighten me.

I typically keep two pistols in my car ( a PM9 and a Sig P238). One I carry in my pocket when I'm out of the car, the other stays in the car as I often need to leave one in my desk at the office. I have been carrying the PM9 for the last three weeks or so, and the 380 has been left unattended locked in the console of my car. Today, just because I hated to see it neglected, I took out the 380 and checked over the ammo. All 6 rounds had severe bullet set back in the casing, with a couple of them almost half the original bullet depth into the casing.

This is not cheap ammo. CorBon High Velocity. I checked some of the same, that I had in a box in the same console and it was all fine. So than I emptied my PM9 which carries Hornady Critical defense. Those rounds were also set back, though not nearly as severe. I checked the 2nd magazine of 9mm that is stored in the same conditions and they were fine.

I started to think that maybe cold had an impact ... but this is Florida and my cars are garage kept. The coldest night time temp has been mid thirties, and not lower than about 60 in my garage at night. My wife carries the same 380 so i checked hers (same ammo) and all her bullets were good. They came from the same box and of the same manufacturer.

A couple of times I can remember tapping the loaded magazines firmly to make sure all the rounds were seated to the rear of the mag .... could this have caused such an issue? I'm not talking about pounding hard on an anvil or anything. Just a firm rap on a desk top at the worst.

Can they be fired in this state ... I've never tried.

Any experience in something like this?
Thanks in advance, Brian

[muggsy]

A firm rap on the back of the magazine on a desk top could have done it.

[OldLincoln]

Set back is not unusual for re-chambered rounds but yours reads a bit extreme. I've read high pressure rounds with set back are dangerous but I don't know about the 380.

[Bawanna]

They might be fine to shoot but at the same time why take the chance. I'd toss em. I'm at a loss why they would set back in the gun. I thought maybe the extra mag in the console might be jostled enough to set back but I doubt that too. I had an old 53 1 ton chevy that would do it but any modern car with suspension I doubt would do it.
No clue on the PM9, or why your wifes didn't do it and yours did. Puzzling?

[Ikeo74]

Are the bullets in question (Barnes solid copper 115 gr hollowpoints)? If so they tend to set back easier than some other bullets. I would not shoot them unless you get a hammer type bullet puller and hammer them enough to bring them back to factory AOL. These loads are already +P or +P+ pressures to begin with and bullet set back will put them into dangerious pressures if you shoot them. You will need a hammer puller and caliper to do this. Don't rap your mags on the desk any more. If you loaded them in the mag and they went down the mag without dragging the tip of the bullet then they are fine (first loading)

[Ikeo74]

A firm rap on the back of the magazine on a desk top could have done it.

^^^^This is the most likely reason for the setback.

[HadEmAll]

You neglected to mention whether you had had chambered and/or rechambered the rounds in question before. One or more times could easily do it. I seriously doubt rapping the rear of the magazine on a desktop, even multiple times, would do it, unless you were rapping it outrageously hard.

[FLBri]

Yes, I often run through the magazine, racking the slide, testing extraction, etc.

I guess I'll stop ... both rapping them and re-chambering. I never knew that would present an issue (re-chambering). I'm going to pitch the .380's and forget about it. The Hornady 9mm CD are not that bad (barely noticeable) and I may shoot them off at the range ... they are not +P.

This chambering thing makes sense ... as the rounds in the extended magazine for the 9mm were fine. I never take that mag out to play around with.

[TriggerMan]

Yes, I often run through the magazine, racking the slide, testing extraction, etc.

I guess I'll stop ... both rapping them and re-chambering. I never knew that would present an issue (re-chambering). I'm going to pitch the .380's and forget about it. The Hornady 9mm CD are not that bad (barely noticeable) and I may shoot them off at the range ... they are not +P.

This chambering thing makes sense ... as the rounds in the extended magazine for the 9mm were fine. I never take that mag out to play around with.

No way would I fire them. Tapping the mag to be sure all rounds are seated should not do anything. I do it regularly. If this brand does this so easily, I would switch to Speer Gold Dots. Sig recommended them in my 238 when they serviced it.

[tv_racin_fan]

Get yourself some snap caps for playing around with. Better than dry firing anyway according to most.

It was the rechambering that did the trick. Just to prove it to yourself take one round out of the box and rechamber it several times then measure it. Some rounds are more prone to this than others. Seems to depend on level of crimp, cannelure or lack of, etc etc.

I read about the issue and checked my carry ammo... doesn't seem to be much of an issue BUT I do check the rounds and when any of them exhibit enough extraction marks it goes in my range fodder box. I don't unload/reload just for the heck of it but when someone wants to check out my handgun or I want to give it a bit of a cleaning I do not hesitate to unload/reload.

[TeamCORBON]

Yes, I often run through the magazine, racking the slide, testing extraction, etc.

I guess I'll stop ... both rapping them and re-chambering. I never knew that would present an issue (re-chambering). I'm going to pitch the .380's and forget about it. The Hornady 9mm CD are not that bad (barely noticeable) and I may shoot them off at the range ... they are not +P.

This chambering thing makes sense ... as the rounds in the extended magazine for the 9mm were fine. I never take that mag out to play around with.

Don't throw them out. Email me next week and we can arrange to have any boxes with our ammo that has set back returned to use and replaced.

Mike@CORBON.com

Thanks,

[jocko]

IMO No way tapping the magazine will cause that. If it does then that parfticular box of ammo is faulty. Now rechambering the same round time and time again will certainly cause set back in practically any rounds. Don't do that,


Not sure I would change rounds but I certainly wold change that box, It can happen and probably has happened to every ammo maker, we just do't read about it and quite possasbley even with that set back the rounds still went bang, so no harm no foul.

CORBON IS GREAT AMMO.
but u may have gotten a bad box. Mike Corbon ask for it bac,k not much better reply than that IMO. They also want to know , instead of just readng about it..

[JFootin]

+1. IMO, tapping (not slamming) the mag shouldn't cause that. Now, the frequent extracting and reloading is more likely a cause.

Great response from CORBON!

[FLBri]

Wow, that is great customer service. I will certainly take you up on that, Mike (Team Corbon).

I am now a reformed re-chamberer... LOL. I hope I don't need an intervention!

Thanks for the help, guys. This all makes sense and I feel better knowing what the problem was.

[TominCA]

My corbon 380's 90 grain HP set back a few thousandths every time I chamber them. I rotate the top round and never chamber one more than twice. Speer Gold Dots do it also - but not as much. I save the ones that have been chambered too many tomes for the range.