Barrel may be removed from vise to determine the serviceability of the barrel. Inspect for foreign matter in gas port (28) of barrel (12). Inspect breech (29) for burrs.
TM 9-1005-313-23&P 0024 00
DIRECT SUPPORT MAINTENANCE OF BARREL ASSEMBLY M240/M240C, NSN 1005-01-044-1026, PN 11825985; M240B, NSN N/A, PN 12976817; M240D/M240G/M240N, NSN 1005-01-408-5897, PN 12976818; M240E1, NSN 1005-01-251-9701, PN 12597035 (cont)
Take off burrs on cylindrical part (30) of breech (29). Take off burrs on rear section (31) of breech (29). Inspect threads for damage.
Replace barrel (12) if removal of burrs affects form, fit, or function or if threads are damaged.
The following define replacement criteria for barrels (12):
• Pits in the chamber of breech (31) are allowable if they are not large enough to cause extraction difficulties.
• Pits less than the width of a land or groove in width or length are allowable. Replace if pits greater than the width of a land or groove in width or length are present.
• Scattered or uniformly fine pits are allowable.
• Tool marks or scratches are acceptable regardless of length. Tool marks will appear as lines running laterally in the grooves or they may run spirally across the top of the lands.
• Definitely ringed bores or bores ringed sufficiently to bulge the outside surface of barrel are cause for rejection. However, faint rings or shadowy depressions do not indicate an unserviceable barrel and should not be cause for rejection.
• Lands that appear dark due to a coat of gilded metal from projectiles should not be cause for rejection.
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