A polymer magwell-insert vise block sized for AR-10 / .308 / SR-25-pattern lower receivers. Drops into the magazine well, clamps in a standard bench vise, and locks the lower flat and stable so you can install a trigger group, torque a castle nut, swap a grip, or run an upper torque without the receiver shifting under load.

Specs & features:

• Fits AR-10 / .308 / SR-25-pattern magazine wells
• Non-marring polymer construction — protects the lower’s anodizing
• Solvent-resistant — safe around CLP, brake-clean, and bore solvents
• Flat clamping faces seat in any standard bench vise
• Use for trigger installs, buffer-tube work, grip swaps, and barrel-nut torque

Insert the block into the magwell, clamp the exposed body in the vise jaws, and tighten until the lower is rigid. This block is .308-pattern only — for AR-15 / 5.56 lowers, use the standard 5.56 magwell vise block instead.