I just got one a week ago. I am using CCI mini mags 40 grain, and Aguila super extra 40 grain. Both with no issues. I have also used some CCI stingers - varmint 32 grain. when I first started shooting the gun , I had a couple of rounds that didnt eject from the stingers. They have a longer casing wich somtimes can cause a problem . When I first got the gun , and the first time I shot it , I was having numerous light strikes and no eject issues. But that was with various cheap ammo I already had . Since then I have purchased better quality , high velocity ammo , and I took the gun apart and cleaned and greased it. Yes , grease , no oil , and I have had o issues with the ammo mentioned above , even the stingers. I would stay away from standard velocity. I really like it so far. time will tell. And Welcome to the forum.