.22 case failure

Karl · 11-12-2019, 10:34 AM

Experienced colleagues,

I was shooting with a friend a few days ago. His gun is a 22 semi-auto rifle from which he has fired hundreds of rounds. A round made an unusual "pop" noise and smoke emerged from the receiver. The action did not cycle to engage another round and we found the torn-off head of a .22 round under the gun.

Upon returning home and examining the gun we found the bullet lodged about an inch ahead of the chamber. I tapped out the bullet with a brass rod (with little effort) and the rest of the case came out with the bullet. The gun was carefully examined before and after cleaning. There was no evidence of a bore obstruction and no evidence of damage. Aside from the flattened nose of the bullet from tapping it out there are no marks on the bullet to indicate an obstruction.

My theory is that the case separation was due to a manufacturing defect. The head of the case separated when the bullet entered the rifling, pushing the breech block back enough to expel the broken head and vent the smoke into the receiver.

I have never encountered anything like this before and would like to know of similar experiences or relevant knowledge.

DavidJayUden · 11-12-2019, 11:25 AM

Wondering aloud if the rifle didn't fire with the bolt slightly open, leaving the rear of the case unsupported?
While I have never experienced such a failure, I do shoot quite a lot of .22's, and generally agree with your theory.
I would also send the 3 parts to Federal for their evaluation.
dju

Doubs · 11-12-2019, 11:39 AM

I agree that the most likely explanation is the rifle fired out of battery; i.e., the cartridge was not fully chambered when it went off.

I'd be looking for a dirty chamber, possibly with a build up of fouling that prevented the cartridge from seating properly. I'd also look at the firing pin to see if it's somehow stuck forward and striking the base of the cartridge before being released or struck by the hammer.

Also inspect the trigger and sear to see if they are worn and the firing pin was released early.

Finally, if the rifle was being fired rapidly, it's possible that the shooter was too quick on the trigger OR the action is dirty and the bolt didn't close as quickly as it normally would with everything clean and lubed properly. Also check the feed mechanism; especially if it's tube fed.

11-12-2019, 10:34 AM	#1
Karl Lifer - Twice Over Lifetime Forum Patron Join Date: Jun 2002 Location: Savannah Posts: 522 Thanks: 0 Thanked 271 Times in 118 Posts	.22 case failure Experienced colleagues, I was shooting with a friend a few days ago. His gun is a 22 semi-auto rifle from which he has fired hundreds of rounds. A round made an unusual "pop" noise and smoke emerged from the receiver. The action did not cycle to engage another round and we found the torn-off head of a .22 round under the gun. Upon returning home and examining the gun we found the bullet lodged about an inch ahead of the chamber. I tapped out the bullet with a brass rod (with little effort) and the rest of the case came out with the bullet. The gun was carefully examined before and after cleaning. There was no evidence of a bore obstruction and no evidence of damage. Aside from the flattened nose of the bullet from tapping it out there are no marks on the bullet to indicate an obstruction. My theory is that the case separation was due to a manufacturing defect. The head of the case separated when the bullet entered the rifling, pushing the breech block back enough to expel the broken head and vent the smoke into the receiver. I have never encountered anything like this before and would like to know of similar experiences or relevant knowledge. Attached Thumbnails

11-12-2019, 11:25 AM	#2
DavidJayUden Patron LugerForum Patron Join Date: Nov 2008 Posts: 4,047 Thanks: 578 Thanked 1,414 Times in 887 Posts	Wondering aloud if the rifle didn't fire with the bolt slightly open, leaving the rear of the case unsupported? While I have never experienced such a failure, I do shoot quite a lot of .22's, and generally agree with your theory. I would also send the 3 parts to Federal for their evaluation. dju

11-12-2019, 11:39 AM	#3
Doubs User Join Date: Jun 2002 Location: Byron, Georgia Posts: 1,698 Thanks: 792 Thanked 1,687 Times in 554 Posts	I agree that the most likely explanation is the rifle fired out of battery; i.e., the cartridge was not fully chambered when it went off. I'd be looking for a dirty chamber, possibly with a build up of fouling that prevented the cartridge from seating properly. I'd also look at the firing pin to see if it's somehow stuck forward and striking the base of the cartridge before being released or struck by the hammer. Also inspect the trigger and sear to see if they are worn and the firing pin was released early. Finally, if the rifle was being fired rapidly, it's possible that the shooter was too quick on the trigger OR the action is dirty and the bolt didn't close as quickly as it normally would with everything clean and lubed properly. Also check the feed mechanism; especially if it's tube fed.