I have a hard time believing you have a Jimenez JA-22 that has been flawless.
Yes, nearly flawless with CCI Stingers when it is clean. Not so with any other .22LR ammo, but it definitely doesn't jam once every magazine, even with cheaper copper/bass coated .22LR. Once the little gun gets dirty, it will jam - it's no Rhorbaugh R9.
I'm not telling anyone to go out and buy Jennings J-22's. It's really not a good defense gun. I just like to plink with it now and then. I'm just reporting that mine, which I've had for over 20 years, is simply not an awful self-destructing jam-o-matic.
But, I will say this - I'll know who has and has not actually shot a J-22 if they can answer this question correctly: What do you hate most
about the J-22? Hint: It has nothing to do with looks, zamac, durability, reliability or accuracy.