Kel-Tec sub 2000
I had one of these in stainless, mine took the Glock mags, though I never actually used Glock brand, I got half a dozen each of the KCI 33 round mags and 17 round mags, then I put +2 extensions on the 17 rounders. They all functioned flawlessly fully loaded. I put a set of Uncle Mikes finger groove slip grips on mine and a vert grip on the rail, which I quickly removed after I saw how much more difficult the case I had selected was to zip up with the gun folded, I then mounted the Sig light/laser combo, after I got the laser dialed in I decided to run hollow points through the gun, thats when the problems came into the picture.
My Kel-Tec sub 2000 WOULD NOT cycle ANY hollow point ammo, regardless of brand. With it being a folding gun, there is no feed ramp, the throat of the barrel is beveled to guide the round into the chamber, no problem when you are shooting the really pointy 9mm bullet, switch to hollow point with even the slightest bit of a flat tip to them and the round slams into the top edge of the chamber, pushing the bullet deep into the case.
My understanding is that this problem does not exist in the .40 cal versions, I didnt know any other sub 2000 owners at the time, so I dont know if the problem was with just mine or all of them chambered in 9mm. So while it was really cool and lots of fun, I sold it to a very happy young man that didnt care in the least that it would not feed hollow points, interestingly, its also the only 9mm I have ever owned that would reliably and consistantly feed round after round of the CCI aluminum cased 9mm birdshot.