I can not speak for all Hi-point 9mm pistols, but I have two of them. Both of them do not like the Winchester White Box ammo. This round is one of the longer 9mm rounds. It loves the CCI Blazer ammo, which is much shorter. I started handloading them with the recent shortage of ammo. I use hollowpoints, and they feed flawlessly. I also have a .40 and it seems to eat anything without any issues. I think that people use ammo that is not favorable to the design of the C9, and mistake it for a jam-o-matic. I know I was very perplexed with mine. I first got it, and put several boxes through without an issue. I got a couple boxes of the Winchester White box, and it started to Jam. I bought some CCI ammo again, and it worked great. I measured the length of the round, and sure enough it was longer. If you do not mind handloading, or finding the shorter 9mm rounds, this is a great gun.