Revolutionary lower design eliminates slack in receiver mounts
Whether you are buying an AR off the shelf, or making your own custom build, extra slack and play between the upper and lower receivers is a problem that plagues the entire AR world. We’re excited to introduce the F&D Defense AR15 mil spec lowers with the revolutionary, patent pending SHUT feature. SHUT stands for Solid Hinge Upper Tensioning. The SHUT feature creates tension between the upper and lower receivers, removing the slack that is common in most AR builds.
Watch the video above as we take three of the most commonly sold AR-15 rifles, all with considerable slack, and mount an F&D Defense lower with the SHUT feature. In each of the three models, the extra slack and play is removed completely.