Cross Machine Tool's Ultra High Precision Rails are engineered to Perform. * Strength-  While not heavy, the UHPR series handguards shine in the strength department. Unlike competitor rails that are only marginally lighter, that feel spongy in the grip hand when squeezed or when side loads are applied to the forward rail, the UHPR stands firm. * Accuracy- UHPR series products are machined to exacting tolerances,  by experienced toolmakers,  at our industry leading Multi-Axis CNC machining facility never outsourced to the lowest bidder. * Function- The UHPR series products succeed in providing function that is demanded by professional users of todays Modern Sporting Rifles. No fluff or gimmicks,  just straight forward functional value in a great looking durable product. * Value- As with any Cross Machine Tool product, value is engineered into the product. * Design- UHPR series products are engineered to provide a durable, trouble free service life. UHPR series rails are compatible with Mil-Spec forged uppers & most billet uppers. * Installation- UHPR series Rails are designed to also provide trouble free installation. Barrel nut does not require timing with gas tube, No shimming of barrel nut required. * American Made- All Cross Machine Tool Products are manufactured Proudly in the U.S.A.