This one-piece aluminum base is machined to tight tolerances for a custom fit. It offers maximum strength for rings to hold tight. Screws are included. Fits Beretta Pintail Slug; BSA Monarch medium action in 222, 243 & 308, long action in 7mm, 270 & 30-06, CF2; Churchill Highlander; Colt Sauer; Howa 1500; S&W 1500, 1600, 1700; Weatherby Vanguard.