My new SG SA M1 from CMP is quite nice, but sometimes the bolt retracts enough to eject , but not enough to chamber the next rd. An old WW2 vet, competitive shooter and multiple M1 daddy advised the prob was likely due to incorrect lubrication.
This strikes me as a bit odd for a rifle that had to function in Iwo Jima sand to Korean ice, but I'm willing to try this out. I know M16's worked better in the desert if Top brought us lots of Break-Free.
I've been using light oils like Wd40. My friend says the M1 is lubed with grease, like Lubriplate and in many more places than the manual says to. I do note that M1 cleaning kits had containers for grease and not for oil.
He recommends the operating rod be heavily greased and this will likely fix the prob.
What say you?