I had been telling folks this gun would feed anything. I guess I lied. I got a 333 round box of bulk Winchester 38 grain copper coated HP from Midway. This stuff works pretty well in my 10/22 and my Mk2, but little brother SR22 chokes on it. It doesn't have enough pop to move the slide back far enough to cock the hammer. Some higher dollar Winchester packed in 100 round plastic boxes like CCI comes in worked fine in the little gun, but not this stuff. Guess that's why Midway had it available, eh? Oh, well, I'll burn it up in my Mk 2 or my 10/22.