Technical data

TM 9-1005-319-23&P 0019
0019-8
ASSEMBLY - Continued
M16A2 RIFLE ONLY
1 7
1 v s 1 5 8
2 8
1 4
1 3
2 2
2 1
2 0
Figure 8. Assembly and Installation of Elevation Knob Assembly.
3. Assemble elevation knob (22), elevation index (13), and new index screw (14) using 1/16 in. key wrench.
Do not overtighten index screw as scale will require adjustment.
4. Install ball bearing (21) and helical spring (20) using needle-nose pliers or tweezers.
5. Depress ball bearing (21) with a punch inserted through access hole, and slide elevation knob assembly
(28) into upper receiver (17) from the side. Center elevation knob assembly.
WARNING
To avoid injury to eyes, use care when installing spring-loaded parts.
NOTE
All springs are identical when new. Once disassembled from the rifle, their free
length may vary due to different amounts of compression when installed. If the
length of springs varies, use longer spring with windage knob and shorter spring in
rear sight base.