Magpul | BEV Block | Black

The BEV Block (Barrel Extension Vise, MAG536) is Magpul's answer to people torquing barrel nuts against an aluminum upper. Steel lugs and a full‑length shank engage the barrel extension so the torque goes into the barrel, not the receiver. Polymer contact faces protect the upper. An O‑ring post uses the bolt carrier for extra stability, and a pin holds the upper in place. Flip it over and it works as a mag‑well block for lower‑receiver work. Made in the USA.