On my Garand, the gas plug appears to be aftermarket, but it does not look like the two popular adjustable ones. I am not sure if it is an adjustable plug or just a regular, non-adjustable aftermarket one. If anyone could fill me in I would appreciate it. It almost looks like a giant screw, but I haven't tried taking it out or adjusting it since my rifle shoots fine. Would like to have an adjustable plug to use different kinds of loads, but don't want to buy one if this happens to be one.