Two-piece clamshell vise block that clamps around an AR-15 or M4 upper receiver, giving your bench vise a rigid grip without stressing the receiver walls or picatinny rail. The correct tool for barrel-nut torque, muzzle-device install, and gas-block work.

Features:

• Two-piece clamshell design — wraps the upper 360°
• Fits AR-15 / M4 forged and billet upper receivers
• Holds the upper rigidly for barrel-nut torque, muzzle-device install, and gas-block pin work
• Bench-vise clamping surface — pairs with any standard shop vise
• No pressure on the upper's rail or feed ramps

Note: this is an upper-only block. For lower-receiver work — trigger pins, buffer-tube castle nut, magwell — use a magwell vise block instead. Trying to run muzzle-device torque off a lower alone will bend the takedown lug.

Wipe the clamshell interior clean before every install; grit trapped between the block and receiver can leave anodizing marks under torque.