M16 Maintenance Manual TM9-1005-319-23.pdf - CombatRifle.net

ARMY TM 9-1005-319-23&P
AIR FORCE TO 11W3-5-5-42
3-18 M16A2 RIFLE FINAL INSPECTION (CONT)
a. FINAL INSPECTION (CONT)
(e)
(f)
Inspect upper receiver and barrel assembly. Barrel assembly should not rotate within upper receiver
assembly.
Check that third or middle slot of compensator is straight up (TDC).
b. TEST
1 Check headspace using headspace gage PN 7799734. See page 3-45, TEST.
2 Check firing pin protrusion using firing pin protrusion gage PN 7799735. See page 3-45, TEST.
3 Check extent of barrel erosion using barrel erosion gage PN 8448496. See page 3-45, TEST.
4 Check barrel straightness using barrel straightness gage PN 8448202. See page 3-45.
c. FUNCTIONAL THEORY OF THREE-ROUND BURST CONTROL (M16A2 AND M4 ONLY).
NOTE
First become familiar with the functioning of the firing mechanism especially when in the SAFE and SEMI
positions. You should also understand the role that the automatic sear plays when firing in the BURST
position. Functioning of the mechanism is explained below In a step by step manner. This actually will
seem to complicate something that is really very simple and happens in less than 1 second. The
diagrams below and on the following pages do not show the associated springs for the sake of simplicity
The positioning of the burst cam is shown in detail
Functional check of three-round burst is as follows:
NOTE
Assume the rifle is fully loaded with a
live round in the chamber and the
selector lever on BURST.
(a)
(b)
Hammer is cocked
Front hook of burst lever is in stop notch
3-88 Change 4