The Patented Arisaka zero retention clamp (ZRC) is engineered to effectively minimize zero shift for lasers and iron sights mounted on the MCX Spear LT handguard. Designed specifically for the Spear LT models chambered in 5.56, 7.62x39 and 300BLK, this version does not support the Rattler. The MCX Virtus and Spear LT handguards lack sufficient upper receiver security, allowing significant flex when minor pressure is applied. This flex can cause a shift of 5 mils or more while the rifle is shouldered, with the zero occasionally not returning to its original position when pressure is released. The Arisaka ZRC features exterior clamps that thread into a specialized U-bracket, engaging the extended upper receiver beneath the handguard. This method securely fastens the handguard to the upper receiver along two axes, effectively reducing or eliminating zero shift. Importantly, the U-bracket does not contact the barrel or gas system, thereby preserving the free-floated barrel configuration. ZRC clamps are designed to minimize interference with the user's hands during handguard grip, ensuring comfortable handling and optimal control.