Used Umarex Electronic Burst Of Steel .177 steel but works fine. I have a paintball tank so you get more shots per fill and an adapter that lets you use the small 12g powerlets but they deplete fast. Also I lost the forward grip and rear sight but it is railed for scope mounts and lasers. Takes 6 AA batteries for the auto trigger. Does 1, 4 and 8 shot burst and has adjustable rate of fire that has 3 different settings. New these cost $130. I only want $40 for this one.