The Geissele HK-10.5" Handguard Assembly 05-190S was built to solve a specific frustration HK416 and MR556 owners run into with generic aftermarket rails: most either require a barrel nut swap or compromise on rigidity to keep the fit universal. This one does neither. It replaces the factory rail while still running the stock HK barrel nut, so nothing about the barrel interface changes just because the handguard did. Machined from 6061-T6 aluminum and finished in Type 3 hardcoat anodize to meet military specifications, this Geissele HK rail is optimized specifically for a 10.5" barrel rather than adapted from a longer design. It measures 10.5" overall with 9 3/8" of that being actual usable rail, sits at a height of 2.51", and weighs 12.96 oz once assembled, enough heft to stay rock-solid without dragging down a short-barreled build. Rail sections attach at the 3, 6, and 9 o'clock positions using steel inserts, giving a steel-to-steel connection that holds up far better over time than threading accessories straight into aluminum. Worth knowing before you order: SMR HK rails don't ship with accessory rail sections included, and you'll need a barrel nut wrench, sold separately, for installation. This Geissele 10.5 Rail was shaped by direct input from operators running the platform in demanding conditions, not designed in isolation and handed down. For anyone building or upgrading a compact HK416 or MR556, this Geissele HK handguard delivers the strength and modularity the platform deserves. Key Features Replaces the standard HK416/MR556 rail using the stock barrel nut Machined from 6061-T6 aluminum Optimized specifically for a 10.5" barrel Height of 2.51", weighs 12.96 oz Steel inserts at 3, 6, and 9 o'clock for steel-to-steel accessory mounting Developed with direct feedback from elite warfighters Type 3 hardcoat anodize finish meets military specifications Barrel nut wrench and accessory rail sections sold separately Geissele HK-10.5" Handguard Assembly 05-190S