I have a M1 Garand in .308 from the CMP.

Today, I was at the range and encountered a problem.  When I would shoot, the recoil would cause the rear sight to go down so that the next round fired would impact lower than the previous round.

When I turn the adjustment knob up and shoot the round would impact where I was aiming.

Here is my question: Do I need a new Rear Sight Elevation Knob ?

Thank you in advance your help.

Tighten the sight at least one more turn.

You need two screwdrivers, one to hold the left screw, the other to push the right screw in and turn it clockwise one click. If one doesn't work, do another.

Thank you.