entropy
Member
I think you are a bit confused, my friend. Adjusting headspace and timing were operations that needed to performed on an M-2HB 50. cal Browning machine gun. The early ones, at least, did not have a quick change barrel Changing the barrel was a time consuming process. The new barrel needed to have timing and headspace adjusted before firing. This was rectified on modern versions.
There are no headspace and timing adjustments on an M-60
"Operator headspace and timing" is Armorer speak for the soldier is an idiot.