Since 1979 I have been using a large blade-type screwdriver turned with a Crescent wrench to tighten and loosen the gas cylinder plugs on my M1 Garands. I finally took some time this morning to machine a badly-needed cross-type wrench to fit the gas cylinder plug, so if anyone has the Garand repair manual handy to look it up, all I need now is to know now how many pounds-feet torque the plugs need to be tightened up to, I sure don't want to have one blow out again! It was awful hard to find.
For what it's worth, the gas cylinder plug and gas cylinder-front sight lock on the barrel muzzle both use a 9/16" by 32 turns per inch pitch thread!
rl849