Inland returned my M1Carbine after five weeks with notation they "replaced the bolt, corrected the timing, and polished the feed ramp." They "tested with 20 rounds of low velocity Armscor--No malfunctions."
This is a most encouraging commentary.
My next move will be to take the carbine apart, look it over paying attention to the bolt and gas port nut, then take it to the range and shoot the hell out of it, examining it after each shoot.
I will report that progress.
It is good to have it back.