Technical data

TM 9-1005-319-23&P 0009
0009-8
TEST AND INSPECTION - Continued
13. Check barrel straightness using barrel straightness gage P/N 8448202. See WP 0015.
NOTE
Review step 14 only if problems are encountered during selector lever tests.
First become familiar with the functioning of the firing mechanism, especially when
in the SAFE and SEMI positions. 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 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.
14. The following is a description of the functional theory of three-round burst.
NOTE
Assume the rifle is fully loaded with a live round in the chamber and the selector
lever on BURST.
1 v s 0 5 4
Figure 3. Beginning Position in Three-Round Burst.
a. Hammer is cocked.
b. Front hook of burst lever is in stop notch.