Mushrooming 22 LR Case - Heritage Rough Rider

[Riomouse911]

I picked this up accidentally when I was picking up my brass at the range last weekend.. I kept it because I had never seen anything like it, or had any idea what could cause it.

Damn what a great forum this is.

That one almost looks like the cartridge was fired without the bolt of a semi auto closed all the way. I’ll guess the head ballooned because it wasn’t supported, but somehow it held up without splitting.
That’s a funky one for sure!
Stay safe.

 

[ih772]

The cylinder has a ridge, that obviously gives an opportunity for back out. I made sure the rounds were seated well. But, somehow they are backing out under pressure.

View attachment 1011139

Like others have said, that looks like a magnum cylinder.