The One-Piece Bullet Proof "Gunsmith" Magwell is CNC Machined from a solid billet of hardened tool steel and can be seamlessly fitted to any standard 1911 frame with the largest magazine well opening possible. This new part is the toughest magwell on the market with a large internal opening that ensures that you never miss a reload again. This oversize, Gunsmith version requires drilling of mainspring housing pin hole to match your individual frame and requires extensive internal machining and blending for best fit.