One other possibility!!!!!!!!!!!!!!!!!!!!!!
My son's DCM M1 came in with a pretty sloppy gas cylinder/barrel fit. A sloppy gas cylinder not being conducive to accuracy on the Garand, I removed the front sight and drilled and tapped the gas cylinder to accept an allen screw down through the top spline. The screw draws the cylinder up tight against the two bottom splines and removes all play. When the sight is replaced, the screw is not visible and any attempt to remove the gas cylinder on this rifle would be unsuccessful.
You might wish to remove your front sight and look if light taps with a block of wood on bayonet lug does not move the cyl.
Regards,
hps