That's the result of an overpressure! I've had one that sounded like a 9mm and blew the head completely off!
Sure yours wasn’t an out of battery or cracked rim? A 22LR out of battery or case rim failure is loud because of the uncontained explosion in the action. Usually the distance the bolt was out of battery will be the same amount of the case length is missing. I have had both occur. The case head failure was 75 year old shorts I was shooting. Almost every fired case had a crack somewhere in it.
Cracking a case longitudinally is bad brass or oversized chamber. A good case should be able to expand enough without cracking. The chambers in all 22LR are way stronger than necessary and will not expand enough for a case to crack even under extreme over pressure.
Yep, impossible for a OOB discharge in a blowback rimfire 22LR. When I google “out of battery 22LR”, I get no search results. Please tell Appleseed so they lift the ban on S&W 15-22’s for OOB discharges.
it is indeed possible for you to get an oob detonation with a .22lr. I have done it back in the day when I was a teen I could shoot 1000s of rounds from walmart in a day. IF you get a stuck firing pin combined with an absolutely filthy chanber it can occur. But short of shooting 1000s of filthy cheap rounds in a day, I do not know how. It happened to me once. I cleaned the gun and the problem was solved
A case split IS NOT THE SAME THING AS a case separation.
PS....dare I say it but......
Case splits are usually a problem with brass quality, a small crack/split at the mouth, a high number of reloads and/or generous chambers.
A case separation.......
Is usually/normally seen with much-reloaded rifle brass (bottle necked brass). There is usually/sometimes a line (that can be seen) that develops just north of the case head. The line is where the brass will usually fail. Long chambers or just reloading the brass too many times (setting the shoulder back has its limits).
Of course, there are exceptions.
If it were ME.....I'd change ammo and see how that goes. If it continues with various brands of .22 LR....it could be your chamber. BUT THEN......it's not like you're going to be reloading a .22 LR.
I have had it happen. Scared me quite a bit as a teen and my grandfather yelled at me for getting my gun so dirty. It is possible if the gun is filthy. A jutting out pin can impact the rim in a gun where the built up crud prevented it from fully chambering and detonate it.Nope! Not in .22 rimfire!