US Patent 9347721 Magazine for firearm

A magazine for a firearm includes a body having a bottom end, a feed end side walls, first and second end walls, a channel on the first end wall, and vertically extending side ridges on the side walls; and a follower including a ridge configured to mate with the channel in the first end wall of the body; a plurality of vertically extending side channels configured to mate with the side ridges of the body; and an arcuate feed surface with an end point of a radius defining the arcuate feed surface being laterally offset from a vertically extending centerline of the follower; and a biasing member configured to urge the follower away from the bottom end.