4 . 5 . 9 Endurance test.
4 . 5 . 9 . 1 Testing of rifles for endurance requirements (see 3.3.26)
s h a l l be accomplished with the rifles held in a firing stand simulating
shoulder firing and conforming to Drawing F7273901.
184.108.40.206 The initial test rifle from each test lot shall be fired
6,000 round regardless of the number of malfunctions or unserviceable
p a r t s requiring replacement in order to complete the test.
4 . 5 . 9 . 3 The rifles shall be assembled with the selector and the
c o m p r e s s i o n helical spring (used with the selector). The firing
schedule for each 300 rounds shall be as follows: 100 rounds semi-
automatics 100 rounds in bursts of approximately 5 rounds each, and
100 rounds in bursts of 20 rounds each. T h e cyclic rate of fire shall
be taken and recorded for one 20-round burst of each 100 rounds fired
i n a 20-round burst. Fully loaded magazines shall be used and they shall
b e used in rotation so that approximately 500 rounds will be fired from
each magazine. D u r i n g semiautomatic firing, rifles shall be checked to assure
t h a t no double shots are fired; and during the interrupted burst firing,
r i f l e s shall be checked to assure that firing stops immediately when the
t r i g g e r i s r e l e a s e d . The ammunition shall be in accordance with 220.127.116.11.
4 . 5 . 9 : 4 The barrel shall be cooled to approximately ambient tempera-
t u r e by air after each 100-round series. Rifles shall be cleaned and
l u b r i c a t e d after each 1,000 rounds, and at the close of each day's firing
t h e rifles shall be protected against corrosion. No cleaning of the
gas system shall be allowed. No parts shall be altered and only parts
broken or worn to the extent that they are unserviceable shall be replaced.
4 . 5 . 9 . 5 Complete accurate records shall be kept for each reliability
test, showing each malfunction and part replacement including the number
of the round at which each occurred.
4 . 5 . 9 . 6 At the completion of the endurance test, rifles shall be
d i s p o s e d of as specified in the contract (see 6.1).
4 . 5 . 1 0 Packaging tests.
4 . 5 . 1 0 . 1 Determination of cleanliness. The applicable surfaces
( e x c e p t for interior surfaces of the barrel, operating rod, gas cylinder,
and flash suppressor) of each sample unit shall be subjected to the
d e t e r m i n a t i o n of cleanliness test specified in MIL-P-116, except that
t h e wipe test shall not be applicable to parts with black oxide or
b i c h r o m a t e protective coatings. T h e interior surfaces of the barrel,
o p e r a t i n g rod, gas cylinder, and flash suppressor shall be wipe tested
for cleanliness using clean white bore cleaning swabs and the degree of
c l e a n l i n e s s s h a l l b e - v e r i f i e d by comparison of-test swabs with standard
swab samples furnished by the c o n t r a c t i n g o f f i c e r .