Don't waste your time or money. Maybe they'll get it right with the 2nd or 3rd release but the first run is garbage. Huge thank you to the guys at rainier though for allowing me to exchange it for a hahn. Even with the mag block being purchased in December. The problems with the cproducts mag are: -It's horrible fit. The block has a fair bit of play while in the magwell (checked on 3 lowers) -Ejector is looser than a craigslist hooker. Loose enough where it will actually move outside of the feed lips on the mag. -Feed ramp is rough and extremely high. The sides are also rough and look to be hand finished (poorly) -With a mag inserted there is easily 1/4-1/2" of play from muzzle to stock at the base of the mag. -12 for cproducts and their inability to produce a decent magblock -23 for cproducts inability to return a phone call or email. +117 for rainier arms kicking ass as usual.