.22 LR case failure.

[fyrewall]

During the past component emergency I acquired a modest amount of .22 LR ammo. I am now starting to use it up. I had a 300 round box of 38 grain Winchester high velocity hollow points.

Upon pulling the trigger on one round, it went off with a much louder report, like a sharp bang, smoke curled up from the top and bottom of my Ruger 77/22 around the rotary magazine. I felt stuff hitting my face and safety glasses. The bolt was much more difficult to open. Examination of that round found a rim that was partially separated from the body of the case. The tiny charge of .22LR powder and hot gas flowing out from a tiny crack did all that, to my surprise.

No damage was done. I continued shooting but can appreciate the M77/22 dual locking lugs, gas escape slot cut into bottom of the bolt, bolt shroud, and good polycarbonate safety glasses.

 

[Jim Hankins]

I continued shooting

The first thing to do in that situation is to make sure the bullet cleared the bore.This is the source of a lot of ringed barrels!

 

[Jimmy James]

Winchester Power Points were bad for doing what the OP said at one time. Did it in my custom 10/22 on several occassions. I still have bricks of that stuff.

 

[fyrewall]

No damage was done, inspection included seeing daylight after pulling bolt & looking down bore. The M77/22 has a great amount of camming action that chambers round and holds bolt against barrel face and when I inspected all, I could see all no crud build up. A small crescent shaped deposit was seen at barrel face/chamber edge where the rim failure occurred. Looking at the case through 10X I can see that the base of the brass and rim looks like it is folded back slightly to cause a split. The split is from 1 - 3 o'clock from the firing pin being at 12 o'clock and right side extractor at 3:30.

I was amazed at the amount of fireworks that occurred during this event - all from a tiny powder charge escaping through a tiny opening. Thanks all for responding.

 

[jepp2]

I was amazed at the amount of fireworks that occurred during this event - all from a tiny powder charge escaping through a tiny opening. Thanks all for responding.

Wait until you have this happen if you want to see some fireworks.

 

[fyrewall]

Thanks for the pic - I have seen pierced primers and blown out primers but never a sort of normal looking primer with a gas leak hole on the side of the primer. I can see other signs of gas leakage. Is this a defective primer or one that was damaged upon seating in that LC mil spec case or was the primer pocket damaged when the crimp was reamed out? The case body just in front of the rim looks gas blasted also.

 

[SSL]

Friend of mine had an aftermarket barrel on a 10/22 that did the same thing with most any round-nose bullet design. It had a "match" chamber with minimal chamber support ahead of the feed ramp. Those round-nosed bullets were just long enough to jam into the lands causing pressure to rise and blow the case rims at the unsupported point. Truncated points worked fine.

 

[fyrewall]

1 out of 300, (Winchester .22 LR, 36 grain hollow point, 1280 fps is .33 percent), small percentage but not good enough. This case rim blew at 12:30 - 3:30 and stopped at the right side extractor. I don't know how other .22's handle gas from split cases or blown rims but I can remember using a Winchester M67 with no eye protection at 8 years old. When this last event happened I felt stuff hitting my face and safety glasses. I probably have fired 10 thousand CCI .22's of different kinds without any problems.

 

[Rsadams]

+1 on the CCI standered velocity over Winchester...

 

[mongo chicago]

Just the opposite. Had a complete case failure with 22 mag. in a revolver. Sent the rest of the box to CCI. They tried to make it my fault with false accusations of storing it by paint. (It was in a gun safe). Got so p***ed off I will never buy another CCI product again.