BKL 260D7 4 Long Drop Compensated Dovetail Mount is the strongest of the BKL mounts. With a sturdy 4 inches of clamp length and 6 dovetail clamp screws, this unitized mount is hard to beat. It is perfect for magnum airguns and semi-auto gun actions. Model 260 is for 1-inch scope tubes and fits all standard 3/8 guns and 11mm airgun dovetail rails. .007 Drop Compensated D7 = 7 thousandths per inch of drop compensation, which equates to 24 minutes of angle at 100 yards. BKL 260D7 raises your group so that you don't run out of vertical adjustment and keeps you closer to the optical center. Technical Specifications of BKL 260D7 Drop Compensated Dovetail Mount: - Fits 1in/25.4mm scope tubes; - Overall length: 4in; - Clamp length: 4in; - Ring Width: 0.6in; - Height from bottom of mount to scope tube's bottom: 0.974in; - Turret Clearance: 0.125in; - Weight: 5.1 oz. BKL Mounts features: - Strong One-Piece Clamping Base allows easy mounting of 1-inch scopes; - Patented Auto-Centering technology solves the problems created by varying mounting rail widths. - Clamping Legs move equally as the clamping screws are tightened keeping the scope centered on the rail. - Oversize mounting rails? No problem. Clamping screws can be switched to BKL's unique  Spreader Holes to evenly push the clamping legs apart allowing the mount base to slide onto the dovetail. - BKL mounts are manufactured from aircraft-grade aluminum alloy on state of the art machinery in Texas. Try BKL, and discover why many shooters use no other mount.