1 Barrel Nut Assembly and Rifle Barrel Assembly a. Barrel nut (t)
Position barrel nut (1) on barrel. Slide barrel nut to the rear of barrel as far as possible.
b. Handguard slip ring (2) Slide handguard slip ring over barrel nut.
d. Retaining ring (4)
Press in from both sides and insert slip ring spring into hand-guard slip ring.
Install against slip ring spring using retaining ring pliers. Snap retaining ring to barrel nut.
retaining ring pliers
Apply molybdenum disulfide grease (item 11, app D) to threads of barrel n' ft assembly before installation.
2 Upper Receiver and a. Rifle barrel Barrel Assembly assembly (5)
Position rifle barrel with aline-ment pin up. Using barrel remover fixture, clamp barrel in vise.
location item action remarks b. Upper receiver assembly (6)
Aline upper receiver assembly using barrel alinement pin and the slot in upper receiver assembly. Install over end of barrel.
Wipe upper receiver thread clean and ensure there are no burrs. Apply molybdenum disulfide grease (item 11, app D) to the threads prior to installation.
Engage threads of barrel nut assembly with upper receiver assembly.
Using combination wrench and torque wrench, torque barrel nut assembly to 35 ft-lb. Torque is measured when both wrenches are used together.
Make certain all three drive pins on combination wrench are engaged with barrel nut assembly. Loosen and repeat torque operation. Then loosen the barrel nut again.
Loosen the vise and aline the front sight base in « vertical position (use a vertical line on the wall to check this) then tighten vise to hold the barrel assembly in that position.
Two time torquing (three times total) procedures pro vide for a better thread fit and prevents barrel nuts from becoming loose.
Do not use the torque wrench for loosening.
barrel remover fixture torque wrench combination wrench
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