Technical data

TM 9-1005-319-23&P 0015
0015-17
CAUTION
Do not torque over 80 ft-lb (108 N-m) while tightening barrel nut assembly to next
hole, to allow for proper alignment of gas tube.
NOTE
Do not attempt to hold upper receiver assembly with pry bar; however, if barrel
assembly turns in holding fixture, a pry bar may be used through front sight
assembly base to help prevent barrel assembly from turning in holding fixture. Use
care not to distort or bend front sight assembly or retaining pins. Use "buddy
system" to hold pry bar.
12. Torque barrel nut assembly (19) again to 30 ft-lb (40.5 N-m) while maintaining sight alignment. Barrel
nut assembly may be tightened beyond 30 ft-lb (40.5 N-m) to align barrel nut assembly serrations for
proper gas tube clearance. Never loosen barrel nut assembly to align for gas tube clearance.
1 v s 1 2 1
1 1
1 9
Figure 22. Alignment of Barrel Nut Assembly.
13. Check alignment of barrel nut assembly (19) with upper receiver assembly (11). The front 8 in. (20.32
cm) of a gas tube may be used as an alignment tool (see illustration). This is inserted into the bolt
carrier key and then inserted into rear of receiver. If parts of barrel nut assembly are properly aligned,
tool will pass freely and lay top dead center along the top of the barrel. A number 15 twist drill (0.180
in.) may also be used as an alignment tool. If necessary, tighten barrel nut assembly to next hole to
allow proper alignment.