Each Weaver Top-Mount Scope Base is machined to the tightest tolerances for a custom fit. They are designed to fight the effects of recoil with a square-cut notch that precisely mates to the sturdy cross bolt in every Weaver detachable ring.Fits:Cooey 71Einfield (Cut like Winchester 70)H and R Models 300, 301, 330, and 370 before 1973; 300, 301 LA Post 1973 (270, 30-06, 7mm, 300 Winchester) Herters J9High-Standard High-PowerInterarms ViscountMarlin Models 455 and MR7Mauser Model 98FN, Swedish 96, and Bauer 3000 and 4000Musgrave Models Mark I-IVNavy Arms Country Boy Muzzle LoaderParker-Hale Models 1000, 1000C, 1100, 1200, and 1700Savage Models 10, 12, 16, 510, 512, and 516 Short Action Rifle, 110 (E and S), 111, 112 (R, V, and FV), 116 FSS (Long Actions); 210 Shotgun - use X-high rings; Striker PistolSchultz and LarsenSears Models 50, 51, 51L, and 53