MIL-DTL-63997C
TABLE I. Malfunctions and unserviceable components Continued
emptied); and failure of forward bolt assist assembly to remain engaged with bolt carrier
assembly during manual attempt to lock the bolt, etc (see 6.4).
5/ Minimum life rounds is defined as the minimum service life of an individual part, whether it
is the original part or a replacement part, expressed in the number of weapon rounds fired with
the part assembled in the weapon. For example, an extractor spring failing prior to firing 2,000
rounds on a new weapon, has not met the minimum life rounds. The failure shall be recorded
and shall be cause for test failure.
6/ The allowable number of serviceable parts shown for 4 weapons combined applies only to
parts failing after the minimum life rounds have been fired on the weapon. For example, ejector
springs failing at 3,500 rounds on one weapon, and 4,100 rounds on a second weapon, fall
within the allowable limits of 2 unserviceable parts on 4 weapons combined however, failure of
an ejector spring on a third weapon after firing 3,000 rounds which exceeds the allowance, shall
be cause for test failure.
7/ Each individual weapon tested shall not exceed the allowable number for each malfunction
in the list or the test shall have failed. When the weapon meets the individual allowable
malfunctions and exceeds the cumulative total allowable malfunctions for a weapon, the test
shall have failed. The combined four weapons tested shall not exceed the allowable number for
each malfunction in the list or the test shall have failed. When the weapons meet the combined
four weapons allowable malfunctions in the list and exceed the cumulative total allowable
malfunctions for four weapons, the test shall have failed.
3.6.7.2 Endurance firing cycle rate. During the endurance functioning test (see 3.6.7.1),
the cyclic rate of fire of the each weapon shall be obtained. The cyclic rate of fire of not more
than one reading on a single weapon or not more than two readings on four weapons combined
shall fall outside of 700 to 940 rounds per minute. The cyclic rate of fire measurement shall be
taken on a three round burst, occurring on the fourth or fifth trigger pull. Ammunition used shall
be Government standard M855, 5.56mm ball cartridges shall be in accordance with drawing
9342868.
3.6.7.3 Endurance target and accuracy. After completion of the endurance functioning
test, each weapon shall be retested for accuracy and shall meet a seven (7) inch extreme spread
requirement for a series of 10 rounds fired. Ammunition shall be Government standard M855,
5.56mm ball cartridges in accordance with drawing 9342868, and shall have a vertical and
horizontal standard deviation at 600 yards between 3.4 inches and 4.0 inches.
3.6.7.4 Endurance barrel assembly integrity. After completion of the endurance
functioning test, the barrel of each weapon shall be free of cracks, seams and other injurious
defects, and the bore and chamber shall be free of pockets, rings, bulges and other deformations.
The chromium plating in the chamber and bore shall be free of nodules, flaking, pits, stripping,
anode burns and evidence of etched base steel. Burrs and sharp edges shall be removed from
chamber edges, and barrel locking lugs. Scratches or marks occurring in a chamber which
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