Each Weaver 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. brbrSpecificationsbrbr- Package Includes 1 Basebr- Material Aluminumbr- Style Weaverbr- Finish SilverbrbrFits brbr- BSA Models Monarch Medium Action in 222, 243 & 308, CF2, Monarch Long Action in 7mm, 270 & 30-06br- Churchill Highlanderbr- Colt Sauerbr- Enfield receiver cut down like Remington 72br- H & R 317 & 322br- Herters U9 Round Receiverbr- Interarms Rossi - Stoeger Howabr- Mossberg 1500 & 1700br- Raptor Arms Same as Remington 700 Long Actionbr- Remington 700, 78, 40X, 721 & 725 all Long Actions in 270, 280, 30-06, 7mm Mag, 300 Win Mag, 264, 375, 458 Cals., 700, 78, 40X, 722 & 725 all Short Actions in 17, 222, 223, 222 Mag, 22-250, 243, 6mm & 308 Cal. & 700 Mzl. Ldr., br- Ruger M-77 round topbr- Sauer 200br- Smith & Wesson 1500, 1600 & 1700br- Shilen Round receiverbr- Weatherby Mark V, Mark V Deluxe & VanguardbrbrNote Mounting Hardware Included.