"It works well in most hammer fired pistols but does not work well in striker fired pistols like Glocks and Springfield XD's. But fires every time in UZI's , MAC 11,MP5 and all 9mm rifles and most pistols."
This is from the site, looks like it should fire from the kel-tec, but I can't say I've had any first-hand experience with it. I can say I have seen a fair amount of brass with the TZZ headstamp, so somebody has been shooting it out of something. I would guess it has been stored for awhile now and would stand another 10 years without any problem. Good luck, hope it shoots fine.