Got a facefull of gas and particles today

[Joe Williams]

I got a faceful of particles today, Sean on one side of me and Cathy on the other got a share, too. Suffice to say the crap on my glasses made me glad to be wearing them today! Not completely sure what happened, to be honest. The outside of the case was black, but the primer wasn't pierced or flattened, the case wasn't split or bulged. The round hit the same area of the target as the others, recoil didn't feel weird (except for my burning face.) The case was, however, a little flat on one side. I've picked up brass at the range before that was slightly mishappen, and resizing it always took care of it, or I tossed the case. Maybe I missed one that wasn't round. This one was a little miscolored, like it may have gotten wet. Best I can think is that the brass had gotten wet while hot, hardened, and didn't expand to seal the chamber, maybe. Checked the gun, checked the barrel, no damage and kept shooting fine, but it was an interesting experience. The smoke coming out of various holes in the gun, like around the hammer, make it clear that quite a bit of gas had come back through the gun. Haven't had that happen in more than 20 years of shooting and reloading.

Does it makes sense that brass that goes into water or snow could harden, and not expand to seal the chamber properly?

Any other ideas about what could cause this?

Edit: I tossed the brass, now I wish I hadn't done that so I could include a pic. Except for being black down the slightly flattened side, though, it wasn't remarkable in any way. I wiped the carbon off so I could check the brass. Like I said, no splits, cracks, or bulging.

 

[shibumiseeker]

What gun?

Two possibilities: Undercharged round not sealing correctly, could be undercharged due to lack of enough powder or could be because of powder contamination (BTDT).

The other possibility is a squib round previously and the second round forced both out the chamber. Check the barrel inside for the telltale donut ring.

 

[daclamdvm]

The case mouth wasn't cracked, was it? You didn't say so, so probably not. I'd guess the bullet/case mouth seal wasn't good. Every now and then I'll find finished cartridges where the bullet is really loose. Sometimes a little extra crimp will fix it, sometimes it won't. I haven't gone to the extent of measuring the case thickness, but I've assumed that was the problem. I tend to use a lot of older and mixed headstamp brass in my .45 ACP (military and commercial). Some of the rounds sound like they fizz when they go off. I've even had the bullet pull out in the chamber and powder get all over. After a few times of that now I just pitch any brass that is like that.

 

[Joe Williams]

What gun?

Two possibilities: Undercharged round not sealing correctly, could be undercharged due to lack of enough powder or could be because of powder contamination (BTDT).

The other possibility is a squib round previously and the second round forced both out the chamber. Check the barrel inside for the telltale donut ring.

Gun was my PT92.

Definitely not a squib round. I was slow firing at the time so would have noticed, and the round before was normal. I've wondered about contaminated powder. But the gun actually cycled (though it showed today it will cycle with some pretty light loads,) and the round went right into the same group as the rest, which tells me it was in at least the same neighborhood velocity wise as the others. When I took the gun down to check it, no donut, no unburned particles. I'd like to think I didn't undercharge, and it didn't feel like it. When I charge the cases, I do each one individually, then set it in a loading block. When I've got 50 or 100 charged, I check the cases against each other, then Cathy double checks behind me.

My thoughts were either the case didn't seal properly because it was out of round, or contaminated powder. Wouldn't contaminated powder have left some behind, though?

Another thought occurred to me as I was typing this. It's possible I could have managed to forget to crimp one. I seat in one operation, then taper crimp in another. Could an uncrimped case have let the bullet go at to low of a pressure for the case to seal properly?

 

[Joe Williams]

The case mouth wasn't cracked, was it? You didn't say so, so probably not. I'd guess the bullet/case mouth seal wasn't good. Every now and then I'll find finished cartridges where the bullet is really loose. Sometimes a little extra crimp will fix it, sometimes it won't. I haven't gone to the extent of measuring the case thickness, but I've assumed that was the problem. I tend to use a lot of older and mixed headstamp brass in my .45 ACP (military and commercial). Some of the rounds sound like they fizz when they go off. I've even had the bullet pull out in the chamber and powder get all over. After a few times of that now I just pitch any brass that is like that.

No, no cracks in the case, case mouth, or the base. No bulges, primer looked like the others. Your post did get me to thinking, though, and I've started wondering if an uncrimped round would have caused the same effect, as I mentioned in the post above.

 

[Joe Williams]

One thing that wasn't normal about the cycling... the case barely cleared the chamber, Cathy said it actually bounced off my right hand. I say it felt normal when I fired, but I was just a tad distracted by the crap in my face, too!

 

[shibumiseeker]

One thing that wasn't normal about the cycling... the case barely cleared the chamber, Cathy said it actually bounced off my right hand. I say it felt normal when I fired, but I was just a tad distracted by the crap in my face, too!

It sounds undercharged, possibly from contamination if your double-check was right. I've had that happen twice, once from oil contamination of the powder, same effects you were talking about. Oil contamination of the powder slows the burning of the powder so it still goes pop but the grains are still burning and it soots really bad.

Out of round doesn't make any sense to me, and lack of crimp doesn't change the burn characteristics that much unless it's bullet setback then the effects are the other direction.

Other than that, without more data I'm out of ideas.