Pass hard. better products out there for the money - AIM Sports Inc AR Lower Receiver Vise Block

Fits loosely in magwells. I had to wrap the block with 2 feet duct tape otherwise a sloppy fit that ruined my mag release due to play in the magwell when torquing on the lower reciever. I used 5 diffrent brands of ar15 recievers and all fit badly. I gave only 2 stars due to once modified it was partly useful.