Rear sight Changes settings
I have a CMP Special Grade M1. The elevation setting will shift when firing. The recoil bounces it around and if I set it at a desired setting (Say 22 minutes up) after a string of fire it shifts as much as 5 or 6 MOA.
Question. How do I tighten the sight to prevent this?
Got This response off the CMP forum
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Quote:
As oldcCop said but a little different. First you MUST tighten the elevation screw as levisdad indicated. Hold the knob as he suggested. Don't grip too tight or you can crack it. Then tighten the center slotted detent screw on the windage knob center only as many "clicks over" or detents as needed to prevent the windage knob from moving. I know it can feel as if your are stripping the threads but it will actually click over as you tighten to the next higher tension detent. Once the windage knob will not move, loosen it one detent at a time until you can barely move the windage knob (it should be moderately difficult to move. The entire sight tension is controlled by the spring under the detent screw. When you tighten it it tightens the windage and the elevation clicks at the same time. If you have the sight apart a little grease on the bottom of the windage knob will allow you to get maximum tension on the detent and still move the windage. You should also be able to put a light coat on the elevation serrations to minimize wear if the "***" on the knob and the receiver serrations are in decent shape.
Once the windage knob can barely be moved raise the elevation to the top and press hard on the aperture. (as you raise it you should notice increased tension on the elevation clicks indicating you've successfully tightened them). When you press on the aperture it should not slip or, it it does, it should only slip with a great deal of pressure applied. If you've properly adjusted the detent enough and it still slips you either have a worn out *** on the elevation knob or, (less likely) seriously worn serrations on the receiver. The elevation pinion will need to be replaced if it's a worn "***". Unless you have the specialized tools needed to replace the knob it's virtually impossible to do without them. Pinions are not really that expensive as a complete unit. If the receiver serrations are found to be the problem about the only solution is to install a lockbar sight which has multiple "tits" to grip the serrations. The later is pretty rare but does happen occasionally.
Tried it, she's tight. Posted for other's reference.