The AR-10 upper receiver block is designed to provide comprehensive support to the upper receiver during barrel installation or removal, effectively preventing damage from torque twisting forces. The block consists of (2) halves - the upper half, which inserts into the AR-10 receiver similarly to a bolt carrier group, and the bottom half, which can be securely bolted to the upper half using the included steel bolts. This configuration ensures full support for both the interior and bottom of the AR-10 receiver while keeping the optics rail accessible for mounting accessories and optics. Additionally, the block features a longitudinal hole that serves as a bore brush guide, facilitating efficient cleaning of the barrel bore. Made from blue anodized aluminum