Full disclosure!
Acquired a Jennings J-22 that hadn't been used in 20 years. Ran a couple of patches down the tube, then went to range. At first, it failed to eject after every round. Slowly improved until it actually worked as a S-A, and it emptied the mag three times over an hour. Still lots of jams. Best was Federal Auto Match .22 long rifle ammo.

I disassembled it, lubed it up and removed the crud. It looked like the firing pin had deformed the edge of the chamber. I removed the bit of metal that seemed to be holding onto the empties and causing the failure to extract. Also smoothed out the feed ramp a bit and brushed the bore.

Went to the range and put 10 mags (6 rounds each) of Federal Auto Match through it. Smooth as silk. Only 1 issue out of 60 rounds -- double feed.

A lot of J-22 owners recommend CCI Stingers. Tried them. Approx. 50-60% did not fire. I could see the firing pin indentation on the ammo. Meanwhile, Federal Auto Match works great. And CCI Blazer work well.

Then I tried Aguila SSS subsonic ammo. After 7-8 shots that seemed normal, I pulled the trigger, and the gun came apart. All that was left in my hand was the lower. The slide came off and flew about 6-7 feet. The firing pin and spring were on the ground, as was the little key that locks the upper to the lower. Weird thing is, nothing appeared to be broken. I cleaned and reassembled it. Seems to function ok, but I did not fire it again.

For sale as a parts gun for the J-22 collector. Comes with one mag and a Bianchi leather holster.