Lower receiver group Inspect hammer and trigger pin holes using plain cylinder plug gage
12006472 Penetration of the gage in any one or more of the four holes will be cause for rejection. Inspect for cracks, corrosion, or mutilation which would affect functioning. Small dents or gouges will not be cause for rejection.
Inspect receiver for corrosion in the lobes of the pivot or hinge pin area. Width between lobes shall not exceed 0 515 inch (1.30 cm). Inspect receiver for break through of metal. Inspect receiver and receiver extension for initial loss of protective coating.
Action spring Free length of spring shall be between 11-3/4 and 13-1/2 inches (29.84
and 34.29 cm) M16A2 ONLY and 10-1/16 and 11-1/4 inches (25.56 and 28.58 cm) M4/M4A1 ONLY.
Handguard Inspect handguard assembly for breaks, separations, and cracks.
Breaks and separations of material which prevent proper retention or interfere with functioning of the weapon will be cause for handguard rejection and replacement. Cracks up to 1 inch (2.54 cm) in length are acceptable provided they do not extend into the handguard retaining flange (1) (critical area).
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