Originally Posted by rcamuglia
This is a Precision Scope Mount. If you want your equipment to be set up as well as humanly possible, it's necessary. You'll need to go to Score High Gunsmithing to get it done as well.

For shooters who are shooting 1 to 2 MOA targets and at Long Range, it's a requirement.

For the dude who's shooting deer and elk at 200 yards, it's a choice. The Reticle Tru will probably be perfect for him.



1. Insure that the scope and action (center of the bore) are in the same vertical plane

This is critical and must be done with an apparatus that can rigidly hold the action. It also must be done with "U"-shaped, accurately-machined metal fixtures that fit over the scope and action simultaneously. The fixtures must fit tightly over the scope tube and action. If any slop exists, thin feeler gauge strips must be added around the action to eliminate the slop.

A "not cheap" level must be used on top of the fixture to level it exactly.

2. Sight through the scope with the rings loose enough to allow adjustments at a perfectly laser-leveled plumb line and turn the scope in the rings to align the vertical crosshair to the plumb line.

3. Tighten the rings. This is tricky because tightening each screw will minutely move the scope and position of the vertical stadia. It may actually take a couple of trys slightly tightening in round robin fashion.

4. Once the scope is tight in the rings and the vertical stadia is perfectly aligned with the plumb line that is perfectly vertical to the center of the Earth, run the elevation knob to each limit while viewing its tracking on the plumb line. It shouldn't leave the line. The scope mounted in such a way that the vertical centerline of the bore and the vertical centerline of the scope has no more variation than one thousandth (.001) of an inch in six inches.

It's common for some scopes to leave the line toward the end of travel. Where they do is considered the top end of "Reliable Travel" and should be noted. Just because the scope is able to dial more before it stops doesn't mean that travel is reliable.

At this point, install a bubble level on the scope while it is in the fixture and perfectly level. Pay attention to it when you're shooting!


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From Score High:

Quote
I have always taken great care mounting scopes. The techniques I had been using were perfectly correct in theory. I simply wasn’t getting the degree of accuracy required. Originally both rifles went through the same process. I got lucky on one, not so lucky on the other. The difference between right and wrong was unperceivable using our old system in the shop environment. I could not get satisfactory results until I built a very elaborate fixture that could rigidly hold a barreled action with the scope mounted in such a way that the vertical centerline of the bore and the vertical centerline of the scope had no more variation than one thousandth (.001) of an inch in six inches.

Some rifles are just good shooters and they make it easy for a good shooter to shine. The performance of some rifles defies logic, and makes it impossible for the shooter to excel. The shooter questions their ability to dope wind. They get frustrated and filled with self doubt when in reality they might just need to have their scope properly mounted.





Good lord RC. What did the world do before that jig?

gravity,a plumb bob and a tiny bit of know how applied while SHOOTING is the end all, no matter how precise your jig.

Charley does build a hell of a rifle, but believe it or not a scope can be accurately mounted without that jig.