American Defense Manufacturing Surefire M600/M300 Scout Mount w/ SF Rail Standard Lever Black AD-SF-R STD. It was designed so that the factory Picatinny rail could be installed and used without having to remove the locking lug from the bolt and thus the spring tension could be applied to the clamp screws and prevent the clamp from coming loose (ie: not seize the lugs). It was Developed w/ the help of ex-military personnel and with the benefit of a proven track-record it became an immediate best seller. You could return this item as the manufacturer does not warrant that the product will fix your problem - it was designed to be used with an aftermarket Surefire Scout Light so you don't have to buy a new one. However if your original mounting system is damaged or in need of major modification please let us know so that we can get you a replacement. This was developed with the help of ex-military personnel. All our Surefire Scout Light adapter plates are to be installed with the factory spec Surefire Scout Light receiver but with the SF lug drilled in the clamp - you must remove the rear lug of the original mounting system (ie the bolt with the small lug removed). Specifications for American Defense Manufacturing Surefire M600/M300 Scout Mount w/ SF Rail: Manufacturer: American Defense Manufacturing Fabric/Material: 6061-T6 Aluminum Color: Black Finish: T3 Mil-Spec Anodize Condition: New Additional Features: SF Rail Weight: 1.75 oz Package Contents: American Defense Manufacturing Surefire M600/M300 Scout Mount w/ SF Rail American Defense Manufacturing AD-SF-R STD: Surefire M600/M300 Scout Mount w/ SF Rail Standard Lever Black