Weaver’s precision-built all steel bases are machined to tight tolerances for a custom fit and a square-cut notch mates to the sturdy cross bolt in every Weaver Detachable ring. Custom hardened fastening screws included. – Fits: – Browning Mauser Actions (Rear base ONLY) – Cil Model 972-C (Rear base ONLY) – Colt 57 (Rear base ONLY) – H & R Models 300 301 330 & 370 before 1973 (Rear base ONLY) – Herters J9 (Rear base ONLY) – Interarms Viscount (Rear base ONLY) – Marlin 455 (Rear base ONLY) – Mauser with receiver ring about 1.410 Diameter(98FN) (Rear base ONLY) – Modern Muzzle Loading Models LK-93 Wolverine Legend Disc & American round receivers (Front and Rear base) – Musgrave models Mark III and Mark IV (Rear base ONLY) – Parker-Hale Models 1000 1000C 1100 1200 & 1700 (Rear base ONLY) – Sears Models 50 & 51 (Rear base ONLY) – Voere Models 2150 2165/1 2165/2 2165/3 & 2165/4 (Mauser Action) (Rear base ONLY) – Weatherby models with FN Mauser Actions (Rear base ONLY)