Model 41's are finicky - especially the new ones with the cheap thin chincy magazines. The best ammo for this particular S&W seems to be the CCI standard Velocity (1070 fps) which is what I use in mine. While some do claim that their M41's smooth out after 500 - 1000 rounds or so, if that does not happen for you I'd send it back to them (WITH ALL your Magazines). To spend all that money for a Target Gun that does not function properly, SUCKS!