How many times has that round been chambered? That’s not a gun problem though, it’s either an ammo problem or user induced.

 

100% no.
What make and manufacturer ammo?
Look like a Hornady Critical Defense.
Also apppears to be a couple of well seasoned rounds.
How many times would you guess this round has been chambered?

 

That’s not good. Don’t shoot those. Thats bullet setback.

That bullet setback increases the pressure of the ammo when fired and might hurt you or damage your gun.

Have you been using it to practice loading your gun? If so, I’d recommend using snap caps instead of your actual ammo.

 

The round on the left IS NOT SAFE TO SHOOT! Looks like a Hornady Critical Defense...thats what I use and have never seen one do that. It will generate extremely high pressure within the case when fired. If you have more doing that contact Hornady with photos and the Lot Number on the box.

 

Those bullets appear pretty oxidized. How old is that ammo, and how often have you re-chambered it?

 

As others have mentioned, you left off some data needed to discuss your issue. What Sig Model? Is it a new from the factory pistol or a used firearm new to you? Have you tried other ammunition in your Sig? What brand of ammunition and is it factory new ammunition or reloads? Have you used the same ammunition with your other pistols?

There appears to be scratches and wear on both rounds. Were there any issues with chambering the rounds other than the setback on the one round?

 

As others have mentioned, you left off some data needed to discuss your issue. What Sig Model? Is it a new from the factory pistol or a used firearm new to you? Have you tried other ammunition in your Sig? What brand of ammunition and is it factory new ammunition or reloads? Have you used the same ammunition with your other pistols?

There appears to be scratches and wear on both rounds. Were there any issues with chambering the rounds other than the setback on the one round?

It’s a brand new Sig P365 and this ammo has been rechambered many, many times. I unload the firearm every night and leave a full magazine in the pistol but nothing in the chamber as we have 3 kids. We are saving to buy a safe since they’re finally getting older. The ammo is Hornady Critical Defense. This has happened to 4 of these rounds since I purchased them, however it has never happened with my Glocks or HK so its curious to me that as soon as I get my Sig, this starts happening. I didn’t realize you shouldn’t rechamber a round more than twice, thanks for the advice guys. I’m curious what you all think about the fact that neither of my Glocks (19 and 43) nor my HK (VP9SK) have had this happen with me doing this for over 10 years?

 

I chamber a round a maximum of 2 times and rotate ammo around to keep track of that fact.

Worth stating again, the setback round shouldn't be fired unless you like boom boom in hand.

 

WOW

 

the round could be catching as it is feeding. i assume you have tried different magazines or ammo?

 

A friend that reloads can "fix" rounds like this by extracting and reseating and crimping the bullet again.

As mentioned, don't fire a round in that condition.

 

It's called setback as many have said. A quality ammo like Hornady almost never has that problem unless it's been re-chambered many times. Occasionally I noticed setback on a round or two, if it's chambered and then not fired, and I remove the rounds for cleaning etc. I fix it with a kinetic bullet puller. A few taps will have the round back out to where it was looking like the others. If you can't fix it that way or the other way that was mentioned, do not fire it and just toss it.

 

I occasionally get one like from re-chambering the top round in my carry magazine, sometimes after just one chambering (even from quality ammo - HST, Gold Dot, etc.). I just keep an eye out for it every time I "unchamber," rotate the top round in magazines, and shoot out rounds in my carry magazines regularly.

 

I used to cycle and shoot out my carry ammo once a week but pandemic prices got me doing that once a month. I would suggest you do the same. It's good to put rounds through your defense mags.

 

I used to do the same thing. Every time I went to the range I'd start with my carry weapon and fire off my self defense rounds before switching to FMJ. Helped build/maintain confidence in my weapon cartridge/choice.

These days though... heh... I'm pretty sure the Hydrashoks in my current pistol are well over 6 months at this point. I'd swap em out, but I only have a box and a half left.

 

Am I the oddball one here that doesn't just release the slide when chambering a defensive round?

 

Yeah, for real.

If I have to de-chamber the gun for whatever reason, I came up with a way to re-chamber the round without it having to hit the feed ramp. I'm sure I'm not the only one who does something like this. It's not straight breech loading, but it is with a twist.

Lock slide back, breech load the round. Holding slide, release slide stop, slowly allowing the slide to contact the round in the pipe. This way the extractor won't slam into the rim of the cartridge. Then, I place my fingers on the left side of the gun, cradling it with the extractor side up. I then use my thumbnails to press the rear of the extractor and it pops right over the rim. Been doing it this way for a long time, and it's just fine. Doesn't hurt anything.

Reduces setback for events like cleaning, or whatever may require you to make the weapon safe, etc.

 

This 100%, been doing this for years. Doesn’t work on all guns thought depending on extractor design but does work on P365’s.

 

I have found this on the Sig 365 ammo. Ammo is pushed back into the casing in two ways. Hand loading into magazine and by repeated racking of round to chamber.

Fortunatley, I'm a reloader and have a bullet puller and was able to extract the affected bullets and reset to depth with a fresh crimp.

Now, after de-chambering a round I will re-chamber by breech loading. (Locking slide open, dropping round into breech and sling-shotting slide into place then insert magazine)

Of course, the best way is to load firearm and leave it loaded...but if that's not possible, the above method is effective.

 

Hey James, you out there? You have lots of us interested and we need more detail. Don't leave us hanging.

 

Never happened to me.

 

Me neither cremaley, I'm interested in the circumstances behind how it happened to the OP. I saw some Remington 357 Sig ammo a couple of years ago that had the bullet pushed in, but I can kind of get it with that ammo, not so much for Hornady Critical Defense.

 

Bullet setback caused by chambering a round several many times.
Just don't shoot it, it can elevate pressure to dangerous levels!

 

I think that y'all trying to trigger my OCD. Now I'll be at the range measuring my rounds with a caliper before loading them into the magazines!

But seriously, thanks for the heads up. I will be measuring any round that was previously chambered before using it again.

 

You should also weigh each round to detect under or over powder charges...

 

LoL minor setback isn't a big deal. Ask me how I know... Now if half the projectile is jammed back into the casing, either get a puller or discard that round. Seriously, a little setback is no big deal. If it's standard pressure ammunition, not +P or whatever, it's fine. The guns are rated for +P, so don't stress. You can google image search how much setback becomes an issue.

 

That’s definitely an ammo issue.

 

I'm totally in your same boat. I just bought a Locking cabinet a couple years back, and a locking ammo cabinet last summer. My boys are now 4 and 5, so it was time to do more than leave them on the top closet shelf, or just de-chambering them, as I used to do, also.

Yes, I can assure, most handguns will cause set back if the rounds are repeatedly chambered; you probably just never did pay as close attention to it until now. The action, ramming the round into the feed ramp, and up and into the breech is not a pleasant event. It can cause setback after just one or two times. Quality ammo with a good crimp, it shouldn't really happen. Just did it with my Sig V Crown, and it didn't set back two rounds I test chambered on my new project.... However, I had some pandemic production era Ammo Inc JHPs and a round nosedove into the feed ramp on another gun. It literally pressed the projectile 2/3 of the way back into the case. Glad I tap rack banged that one outta the way, and picked it up to examine and discard it. Good crimping is good.

 

Yeah, it won't work on guns with shorter extractors like Glocks, etc. Glad I wasn't the only one doing this

 

Apparently something went right over my head throughout this post, although I admit I am simultaneously busy with more important things at the time. What won’t work on guns with shorter extractors?

 

The pressure on the bullet causing it to uncrimp and push back in the case happened at the feed ramp, not the chamber. Glock chamber being large has nothing to do with anything, rechamber the same round over and over in a Glock and eventually it’ll do it too.

 

Thank you. It has to do with the nose of the round ramming into the bottom of the feed ramp. If you slowly cycle a gun, holding everything tight and slowly allowing it to work, you can observe this. Even an AR-15 operates by the same principles. Also, it probably won't cycle or load the round properly when doing this in hand holding slow motion, as it's a quick, violent action that is timed and designed to work under certain speeds, force amounts, spring tensions, etc. The round getting jammed into, and up the feed ramp is not a nice process, but it works very quickly, so we many times never really see what happens, as it happens.

The way headspacing works, the chamber itself won't ever really cause set back. Even if the 9mm round was slightly out of spec on the larger side, which I have seen, it's probably less likely to loosen at the crimp and set back. It probably won't go into battery, or eject very nicely, either.