best method to square scope to the receiver

[mocos]

what is the best way to mount a scope to avoid having the crosshairs or reticle canted off perpendicular.

[Tony.]

Go to an auto parts store and get a set of feeler gauges with removable gauges.

The top of the base is flat. The bottom of the scope is flat. Put the gauges under the scope and then slide them out and continue to tighten. You can add and remove gauges to adjust the height required.

This is assuming that you do not have one of the Leupold canted reticle specials...

[Mstnpete]

Purchase a tool called LEVEL, LEVEL, LEVEL By Wheeler Engineering from MidwayUSA. The device has one level with a built-in magnet that attaches to the rails of a bolt-action rifle for leveling the gun in a vise. With a second level positioned on top of the turret, the scope is adjusted until it is level. The crosshairs of the scope are then aligned and true to the horizon. The Level-Level-Level works on most bolt-action rifles and may be adapted for other firearms.

http://www.midwayusa.com/viewproduct/?productnumber=529349

[mocos]

Go to an auto parts store and get a set of feeler gauges with removable gauges.

The top of the base is flat. The bottom of the scope is flat. Put the gauges under the scope and then slide them out and continue to tighten. You can add and remove gauges to adjust the height required.

This is assuming that you do not have one of the Leupold canted reticle specials...

the scope that I want to mount does not have a flat bottom and I think you are suggesting something other than what I am trying to do.
...not trying to adjust the height of the scope...I want to have both the horizontal plane of the rifle and the scope to be the same...I do have the wheeler spirit levels but they appear to be somewhat coarse.. I had originally mounted the scope and had it zeroed at 50yds doing 1 moa..then took it to 200 yds and it wasn't even on paper ....checked it again and the vertical reticle was slightly off vertical or perpendicular to say.. the picatinny rail.....it is close but not exact...how do they do it for say..bench rest rifles which need it to be "exact"

[MAX100]

If it is a bolt action.

*Check the sling stud to see if it was installed straight. If so mount a bipod on it straight.
*Use a level table or bench and mount your base. Put a level on the base to check to see if it's level, if not, bed it so it is.
*Mount your rings place your scope in the rings check to see if the scope slides freely in the rings. If it binds, the rings will need lapping.
*Tighten the ring halves evenly a little at time to almost tight on the scope tube but so you can still move the scope in the rings.
*Setup a plumb line or use something that you know is plumb like the corner of a brick wall. Then put the cross hairs straight on the line. Get your scope in the right position so you get the best eye position and cheek weld on all the magnifications. Comfortable for you.
*Put a level on the top of the turret and see where the bubble is located. *Take the level off and tighten the rings a little at a time checking with the level to see if the bubble is in the same place. Tighten the screws to 15 in/lbs.

Now check your work. Adjust the elevation turret all the way to the bottom and set your cross hairs at the bottom of the plumb line and slowly adj the turret up and run the plumb line. If it runs the line straight you are done.

*Get a torque driver or wrench in in/lbs or borrow one
*Sling stud needs to be straight
*Bipod needs to be straight & level
*Table or bench needs to be level
*Use a quality base mount. The Base needs to be mounted level on the receiver. Bed it if needed to make it level. Use blue Loctite on the base screws only.
*Use a quality set of rings. If needed lap the rings.
*Mount your scope low as possible without it touching the barrel.
*Don't over tighten the ring halves and bind your scope tube and possible damage the scope or break a screw off.
*Check your work


Good luck!



GC

[Mikeb]

When I did mine I used a plumb bob. I put the rifle in my home made cradle then focused on the plumb bob string hanging across the room.
good luck
Mike

[Pryde]

the scope that I want to mount does not have a flat bottom and I think you are suggesting something other than what I am trying to do.
...not trying to adjust the height of the scope...I want to have both the horizontal plane of the rifle and the scope to be the same...I do have the wheeler spirit levels but they appear to be somewhat coarse.. I had originally mounted the scope and had it zeroed at 50yds doing 1 moa..then took it to 200 yds and it wasn't even on paper ....checked it again and the vertical reticle was slightly off vertical or perpendicular to say.. the picatinny rail.....it is close but not exact...how do they do it for say..bench rest rifles which need it to be "exact"

No, you are not understanding what Tony is saying.
What he is telling you is the quickest and most accurate method of mounting a scope.

Here is a tutorial with pictures. You can eyeball it with the other method suggested, but the feeler gauge method is the best.

http://www.snipershide.com/level

[Captain Evilstomper]

here's another one, level the rifle in a rest, THEN use a plumb bob on the wall.

[HondaMasterTech]

Seems like the scope rings are determining the level"ness" of the scope, in the end. I dont get the point of the feeler guages.

[Tony.]

Seems like the scope rings are determining the level"ness" of the scope, in the end. I dont get the point of the feeler guages.

The scope rings keep the scope level fore and aft. The feeler gauges level the scope left and right. The flat bottom of the scope squishes the feeler gauges down to the flat scope rail. Hence, your scope bottom and rail are parallel. Assuming you are not using a scope with a canted reticle, your crosshairs should be level.

[mecam]

Feeler gauges works best on real brand name scopes. Doesn't quite work with some Chi-com made scopes because quality control sucks that the body is not square with the reticle to begin with.

[HondaMasterTech]

The scope rings keep the scope level fore and aft. The feeler gauges level the scope left and right. The flat bottom of the scope squishes the feeler gauges down to the flat scope rail. Hence, your scope bottom and rail are parallel. Assuming you are not using a scope with a canted reticle, your crosshairs should be level.

OOOHHHHHHHHHH I get it now. Makes perfect sense. Thanks.

[MAX100]

A feeler gauge doesn't work will all scopes, leveling with a plumb line does.

The holes on the receiver are sometimes drilled a little off center causing the base to be unlevel when mounted. The base sometimes has to be bedded to make it level.



GC

[Religious Shooter]

So if you bed the base to make it level... why wouldn't the feelder gauge work?

The feeler gauge works off the base... and you just said the base was bedded to make it level.

[MAX100]

So if you bed the base to make it level... why wouldn't the feeler gauge work?

Everyone was taking it for granted that the base will be level when mounted. I was saying that is not the case with all rifles. If you level a scope with a feeler gauge off a base that has not been mounted level, well you know the outcome.

A feeler gauge doesn't work will all scopes because not all scope have flat bottoms. The base can be off by just few degrees and some reticles can be canted by a few degrees. If that is the case it is best to level the reticle to the bore axis using a plumb line.

Level a reticle how you choose. I have had good luck with making sure everything is level first then use a plumb line to level the reticle.


GC