WP 0018 00-3 in the M2A1 machine gun’s TM 9-1005-347-23&P (Jul 11) says to inspect the bolt face for pits and/or eroded areas up to .062 inches long or wide, .031 inches deep in scattered or random patterns, or rings .031 inches deep and .062 inches wide.
I have bolts with eroded areas beyond .062 inches in length and width, but they don’t meet the criteria for depth. Do they need to fail in length, width and depth to be considered NMC?
Good question, sir.
If a bolt fails just one of the length, width or depth criteria, it’s NMC!