Ar-15 barrel installation, barrel installation, barrel

Installing an AR-15 Barrel

Your torque wrench will earn its keep on this one.

By Bryce M. Towsley (RSS)
May 24, 2011


Barrel nut



DPMS Multi-Tool or other barrel wrench
Brownells upper-receiver action block with insert
Torque wrench with 1⁄2-inch drive
Bench-mounted vise

The YHM free-floating fore-end I chose for this build came with a barrel nut. The following instructions are for installing the barrel using this hardware and are typical for fore-ends of this type. However, the process may vary a bit with other models.

Slide the action-block insert inside the receiver to support it and prevent distortion under pressure. Then clamp the receiver in the action block, and secure the works in a bench-mounted vise.

Clean the receiver threads with a small brush, and coat them with an anti-seize compound or high-quality grease. Insert the barrel through the front of the receiver. Thread the barrel nut onto the receiver with the wide, threaded portion to the rear. Tighten the barrel nut using a DPMS Multi-Tool or other barrel wrench.

The Multi-Tool is designed to be used with a 1⁄2-inch-drive torque wrench. The mil-spec tightening technique is as follows: Torque to 35 foot-pounds. Loosen. Torque again to 35 foot-pounds. Loosen again. Torque past 35 foot-pounds, until the next hole in the nut aligns with the gas-tube hole in the receiver, but do not exceed 80 foot-pounds.

Ar-15 barrel installation, barrel installation, barrel

The Brownells upper-receiver action block and insert help secure the upper for installing the barrel and other components. Put the insert in the action, put the action in the block and clamp the block in a vise.

Ar-15 barrel installation, barrel installation, barrel

After aligning the barrel with the receiver and installing the barrel nut, use a torque wrench in conjunction with a barrel wrench to properly tighten the nut.

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6 Responses to Installing an AR-15 Barrel

  1. Pingback: Building a Home-Defense AR Upper | Shooting Illustrated

  2. Pingback: My AR Project - Page 3 - WaltherForums

  3. Steve says:

    I am going to disassemble my new ar15 and I have bought the special tools required. Your pics & torque specs are great. This is what I needed to make sure it’s done correctly. Thank you, Steve

  4. sean says:

    I heard something about anti sieze becoming corrosive and not to use it and can never get a straight answer about what grease to use. Please help . The rest of ny parts are finally on there way

    • Evan says:

      I dont know if This is too late for you to see it but from what I’ve heard you need to avoid using anti-seize that has graphite in it since that can harm aluminum. I’m not sure about more than that but look around on some of the forums for recommendations.

  5. Steve says:

    The mil-spec grease for an AR barrel nut is Aeroshell 33 MS. Palmetto State Armory sometimes stocks small, .5 oz tubs.

    It’s is NOT the same grease as Aeroshell 33.

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