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AR action plumb? Mounting scope?

rmiked

Sergeant of the Hide
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Minuteman
Nov 8, 2023
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I am new to ARs. When I mounted my scope on my REM 700, Wheeler makes an action rail bubble level to determine when the rifle is plumb with gravity. The magnet sticks to the 90 degree rails, very neat. When I mounted my scope on my Seekins SP10, I used a bubble level on the picatinney rail to determine rifle being plumb with gravity. Am I correct that ARs don’t have nice 90 degree action rails? Removing my BCG it looks like a cylindrical shape inside upper with edges that are not 90 degrees. Is the standard practice to use a level on the picatinny rail or is there a special tool (like the Wheeler action rail level) for ARs? Thanks
 
I mount rifle in gun vise and level the rail. While I have the little Wheeler bubble levels, I prefer a larger level for accuracy. Then level the scope on the elevation turret.
 
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Be aware that it is as likely as not that when you actually shoulder the rifle, the reticle may not be level to gravity, even if it is level to the rifle. It is more important that the reticle be level as you shoot the rifle, than strictly level to the rifle.

Level the scope to the gun. Then shoulder the gun with your eyes closed. Open your eyes. Is the reticle level? Do this a dozen times or so, to prove to yourself that you do (or do not) shoulder the rifle with a level reticle. If not, adjust the scope as necessary.
 
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I don't use levels for the most part when mounting optics. I put the rifle in the vise, attach the mount, and use feeler gauges to level the bottom of the turret globe to the mount (ostensibly to the top of the picatinny rail too) and then torque the ring caps down.

Feeler Gauge Leveling.jpg


I know it's not the most in vogue method but it's how I've been doing it for years and it's been working pretty well for me. If I'm feeling froggy I'll check it against a plumb line and level put on the pic rail.
 
I don't use levels for the most part when mounting optics. I put the rifle in the vise, attach the mount, and use feeler gauges to level the bottom of the turret globe to the mount (ostensibly to the top of the picatinny rail too) and then torque the ring caps down.

View attachment 8327896

I know it's not the most in vogue method but it's how I've been doing it for years and it's been working pretty well for me. If I'm feeling froggy I'll check it against a plumb line and level put on the pic rail.
Thats basically what I do as well. I level the scope in the one piece mount using feeler gauges or the leveler that comes with the mount. I then install the scope/mount on the rifle. Been doing this for 20 years now.
 
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I mount rifle in gun vise and level the rail. While I have the little Wheeler bubble levels, I prefer a larger level for accuracy. Then level the scope on the elevation turret.
I do this, but also check to see how the reticle matches up with a plumb bob.
 
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Bore sight on a plumb bob with a flourescent colored string. Center the string in the bore and align the vertical crosshair with the string. Done. The adjustments will track exactly with the bore.
 
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I don't use levels for the most part when mounting optics. I put the rifle in the vise, attach the mount, and use feeler gauges to level the bottom of the turret globe to the mount (ostensibly to the top of the picatinny rail too) and then torque the ring caps down.

View attachment 8327896

I know it's not the most in vogue method but it's how I've been doing it for years and it's been working pretty well for me. If I'm feeling froggy I'll check it against a plumb line and level put on the pic rail.
I use Allen wrenches, I can usually find one that with a little twist gives me the parallel reference that will not get stuck.
 
Arisaka makes an inexpensive sine bar level kit for squaring the mount to the scope, the Allen wrench works well, and so do the feeler gauges.

And I like using the plumb/level line to add my bubble level. Then I know everything is pretty much perfect.
 
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this turned out to be a recurring task for me, every time I build an upper, then mounting the scope, scope mount, or swapping scope mounts.

I bit the bullet and bought the Badger Ordnance scope leveling set-up tool, about 5 yrs ago, along with a steel-block bubble level.

buy once, cry once. But i've used it often enough now that it's been worth it.
 
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