Bolting the two halves of the upper receiver block fully supports the upper receiver to prevent damage from torque twisting forces when installing or removing barrels from the receiver. The upper half of the block inserts into the AR10 receiver just like a bolt carrier group. The bottom half of the block can be bolted together with the upper block half with the provided steel bolts. This fully supports the inside and the bottom of the AR10 receiver, and it also leaves the receiver optics rail open for mounting accessories and optics.

Specifications:

• The AR10 upper receiver block also has a hole through the length of the block to act as a bore brush guide for cleaning out the bore of the barrel. For easy cleaning.
• Constructed with blue anodized Aluminum.
• Made in USA