The BEV Block (Barrel Extension Vise) is an all-in-one, compact vise block tool for AR15/M4 assembly operations of barrel nuts, flash hiders, etc. The BEV Block mounts securely in a vise and provides support for both billet and forged upper receivers. It engages the barrel extension with solid steel lugs and a full length support shank to prevent flexing. Steel hardness is optimized for durability, yet won't damage the barrel extension, and Magpul Polymer is used for all other engagement surfaces to protect the aluminum receiver. An o-ring post uses the bolt carrier for additional stability and the included pin keeps the upper in the proper position. The BEV can also be turned over and used as a mag well vise block to support the lower receiver for maintenance or other operational needs. Made in the USA.