250 gr shockwaves backed by 120 grains of pyrodex. Last year was my first year with this gun and I really like it. great accuracy. I've got a nikon prostaff on top but last year hunted with the pine ridge that it came with from cabelas. I killed a doe, about 110yd shot. She died after about a 150 yd run although she was hit right in boiler room. The only thing I didn't like is there was no real blood trail to speak of. Without hitting bone, I think most ml slugs just don't expand much, at least in my experience.