As stated above, yes. It's stamped 5.56x45mm on the side. Be careful, when I bought mine, apparently CSA had a bad batch of rifles which were over gassed from factory. When I would fire a round, it would shoot 30 feet in the air and 30-40 feet away from me. As it was my first Czech rifle, I didn't think anything of it until a corner of the breech block broke off and a hairline crack formed down the centre of the bolt. I emailed CSA, and they pointed me to their only warranty centre in Canada, Movie Arms Group. I called them to set it up, and it just seemed very sketchy. He didn't ask for my pal, and just a bunch of other things that threw up red flags. I talked to my local gunsmith, and he vouched for them, so i have decided to go through with it, but life has got in the way and I have a 1000+ dollar paperweight sitting in my safe until now. Anyone have any experience with these guys?