M1 Garand elevation won't stay still

[strat81]

I tried sighting in my Garand yesterday at 100 yards. A friend spotted for me and I'm going through ammo...
"Bring it up...closer. You're low again... closer. Good. Uh oh, low again."

Jeez. Then, after going through maybe 4 or 5 clips, I notice that the elevation knob is clicking itself down under the force of the recoil!!!

These are "normal" Garand sights, not lock bar sights. The screw is tight. What can I do to fix this?

This is only the elevation knob doing this, windage is fine.

Also, any links to how to zero an M1 would be nice. I found a few sights with it, but most rehashed the same stuff and were confusing. I have 25 and 100 yard ranges at my disposal, 200 maybe.

 

[30Cal]

Google a copy of the garand field manual--FM 23-5 I believe. Setting the tension on the rear sight is covered in the "Regular Maintenance" section.

 

[strat81]

(d.) Obtaining the proper rear sight tension is extremely important; without it the sight will not hold its adjustment in elevation. During normal maintenance and prior to firing, the rear sight must be checked for correct sight tension. The indications of improper sight tension are: elevation knob extremely difficult to turn, and elevation knob turn freely without an audible click.

(1) If the elevation knob is extremely difficult to turn, the soldier must rotate the windage knob nut (with the scew-driver portion of the M10 cleaning rod handle) counterclockwise one click at a time. After each click an attempt should be made to turn the elevation knob. Repeat this process until the elevation knob can be turned without extreme difficulty.

(2) In the event the elevation knob is extremely loose and the rear sight aperture will not raise, the windage knob nut must be turned in a clockwise direction, one click at a time, until the aperture can be raised.

(3) To check for proper tension the procedures listed below should be followed:

* (a) Raise the aperture to its full height.
* (b) Lower the aperture two clicks.
* (c) Grasp the rifle with the fingers around the small of the stock and exert downward pressure on the aperture with the thumb of the same hand.

(4) If the aperture drops, sight tension must be adjusted. To do this the windage knob nut must be turned in a clockwise direction one click at a time until the aperture can no longer be pushed down. If the proper tension cannot be obtained, the rifle must be turned in to the unit armorer.

.30 cal, I followed the above procedure as detailed in the field manual. The elevation knob clicks but is not difficult to turn. The windage nut has also been tightened.

Is this worth disassembling the sight? I.e., if I disassemble it, are there any blatant signs of wear I could check for? Maybe I'm doing it wrong, who knows.


Another point to add, when it loses elevation, it stops at a certain spot. For the sake of argument, I'll set it at point F and it'll drop to point D and won't move from point D. It won't drop down 5 (or however many) clicks and stop at the bottom.

 

[30Cal]

I'd pull it apart just to be sure. Does the aperrture flop about in the base? The spring cover should have enough bend to it to apply pressure on the aperture.

 

[Trebor]

How many clicks is the sight set up from the bottom?

Just asking because the first few clicks up from the bottom are "dead" clicks. The sights are known not to stay set at those clicks. We're talkinga bout four or five clicks up from the bottom, max.

Other then that, sounds like it just might be worn internally. I'd get instructions on how to take it apart and then see how it looks.

 

[strat81]

The aperture does not flop around and seems pretty solid.

Not sure on the number of clicks, I'll have to check tonight. I'm 99% sure it's more than 5 clicks up.

 

[strat81]

UPDATE

It was exactly 5 clicks up.

I tried pushing down on the aperture and it would not move. I did some minor disassembly of the sight. I unscrewed the windage and elevation knobs and removed them and the aperture from the sight base. The receiver detents and the splines/grooves on the elevation knob all looked good. There were no obvious worn or damaged parts. I cleaned and reassembled those parts.

I tightened everything down TOO MUCH so it wouldn't move. I loosened them up just a wee bit so there's resistance that is stiffer than it was before. On the plus side, the sight isn't moving when I operate the action (which it was doing before). Hopefully this resolves it. I'm not sure when I'll have the old girl out next.

Any other suggestions would be appreciated.