Leupold

Mark 4 Tactical Bases are the only bases to accommodate both the oversized 8-40 screw and a 6-48 screw, providing compatibility with the widest range of modern tactical firearms. Both styles of screws are included with each Mark 4 base. Fits- Remington 700/721/725 (RH, SA), (also BSA Monarch, Mossberg 1500/1700, Remington 700 Muzzleloader & Ruger M77 Round Receiver).