The Rock River Arms M4 Stock Wrench (brand part no. AR0165) is a purpose-built armorer’s tool for installing and removing the castle nut and buffer tube on M4-style collapsible stock assemblies. It’s sized to fit the standard AR-15/M4 castle nut without slipping or marring the finish.

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Key Specifications

• Brand: Rock River Arms
• Category: Gunsmithing Tools & Gunsmith Supplies

Frequently Asked Questions

What does the M4 stock wrench fit?
It's sized for the standard castle nut used on AR-15/M4 collapsible buffer tube assemblies.

Can this wrench be used for both installation and removal?
Yes, it works for torquing the castle nut down during installation and for removal during a stock swap.

Order the Rock River Arms M4 Stock Wrench online now from Schaefer Defense and get it shipped fast.