Rifle Scopes Leveling scope with feeler gauges.

[JMGlasgow]

This was mentioned in another thread and figured I'd start a new thread instead if hijacking.

How does a person level a scope with feeler gauges? I'm having trouble picturing how that is done.

Could someone explain in detail?

 

[Km22]

This was mentioned in another thread and figured I'd start a new thread instead if hijacking.

How does a person level a scope with feeler gauges? I'm having trouble picturing how that is done.

Could someone explain in detail?

In short, the bottom of the scope is flat and the base is flat. You stack the feeler gauges in between and tighten the rings down. The reticle SHOULD level in quality scopes.

 

[280nosler]

IF you have any new business cards, and are using a picitinny rail, mount the scope with at least enough room between the rings to put the stack lengthwise (down the action). Mount the scope, and add or subtract card until it is a tight fit. Lock down the ring screws when it is good and tight. Remove cards and lock down the rings to the base (torque it down).

 

[Km22]

I have also used playing cards

 

[JMGlasgow]

I'm assuming this can't be done with a 2 piece base.

 

[rljatl]

Yes, it can. Actually, it is easier with a two piece base. The flat spot on the scope is under the turrets.

 

[JMGlasgow]

Your picture is showing a 1 piece base.

 

[rljatl]

Your picture is showing a 1 piece base.

Looks like a two piece base on a picatinny rail to me.

 

[JMGlasgow]

Ok, maybe a difference in terminology. A base to me is the part the rings mount to. So what I am seeing is a one piece picatinny rail.

 

[rljatl]

Yeah, you're probably right. How about this - The scope mount (rings) is two piece and it mounts to a one piece picatinny rail base?

 

[JMGlasgow]

Ok.

What I have is a two piece picatinny mount. So the feeler gauge method probably won't work.

 

[Temp9]

Correct. But if you turn the scope to the lowest magnification, you can position your head a foot or so behind the scope and still see the reticle. Position the vertical line of the reticle so that it would intersect the center of the bolt or the center of the picatinny rail if extended. Bam. Leveled.

 

[HD1911]

Hang a Plumb Bob with a Bright Neon Cord from something, then lay behind the Rifle, while prone, gripping it naturally and keeping it pressed into your shoulder, like your going to Fire it. And simply align the Vertical Reticle Stadia to the Plumb Bob...End of Story.

 

[MoBoost]

Feeler method assumes that: recoil lug is square to the bore, that the receiver is tapped square, that the picatiny bottom is machined square to the mounting holes, that the picatiny bottom is square to the top, that scope bottom is square to the top and that the elevation knob is square to the reticle.

Plumb bob assumes that today's forecast for gravity is "present".

Your choice.

 

[elfster1234]

http://www.snipershide.com/shooting...ve-way-leveling-scopes-when-mounted-pics.html

This was mentioned in another thread and figured I'd start a new thread instead if hijacking.

How does a person level a scope with feeler gauges? I'm having trouble picturing how that is done.

Could someone explain in detail?

 

[Pinecone]

BUT, the important thing is that the reticle is level WHEN YOU SHOOT.

So you need to find your natural point of aim, and adjust the scope that the reticle is level THEN. Use a plumb bob to determine vertical.

 

[Bradu]

Ok.

What I have is a two piece picatinny mount. So the feeler gauge method probably won't work.

I have removed a scope off of a one piece base on a different rifle to level a scope then remounted the scope. It's quicker to do that since it only takes a few rounds to rezero.

 

[hermanow]

BUT, the important thing is that the reticle is level WHEN YOU SHOOT.

So you need to find your natural point of aim, and adjust the scope that the reticle is level THEN. Use a plumb bob to determine vertical.

Actually the recticle needs to be level with a rifle that is leveled side to side, furthermore, you need to have it level side to side WHEN YOU SHOOT. Otherwise any elevation changes you make will also change horizontal p.o.i.

 

[LRDD]

I thought Lowlight had a really good video of doing it with the feeler gauge but I can't seem to find it anymore.

 

[264shooter]

I use this method and I incorporate an IOTA to see the plumb line.

BUT, the important thing is that the reticle is level WHEN YOU SHOOT.

So you need to find your natural point of aim, and adjust the scope that the reticle is level THEN. Use a plumb bob to determine vertical.

 

[scudzuki]

Feeler method assumes that: recoil lug is square to the bore, that the receiver is tapped square, that the picatiny bottom is machined square to the mounting holes, that the picatiny bottom is square to the top, that scope bottom is square to the top and that the elevation knob is square to the reticle.

Plumb bob assumes that today's forecast for gravity is "present".

Your choice.

Agreed, gravity don't lie, but for this to work, you need to hold the rifle perfectly plumb as well, and what are you using for a reference suface? Most likely the top of the Picatinny rail.
The feeler method only requires that the receiver and rail are properly machined... has nothing to do with the recoil lug assuming that it is not interfering with the stock; if that is the case, that needs to be fixed before continuing.

If the turrets are not square to the flat on the bottom of the turret housing then you've got even bigger problems... your scope is JUNK and needs to be replaced.

If the reticle is canted relative to the turrets then it needs to be fixed, unless you are only going to use holds or turrets for corrections, but not both.
If the reticle is canted and you are always going to use holds then the reticle needs to be plumb; if you're only going to dial corrections then the turrets need to be plumb/square.

Me, I only buy quality scopes with turrets properly indexed to the turret housing and reticles correctly clocked in, and all of the rails I've mounted have been close enough to square that I am unable to measure any deviation, so I use precision gage pins to mount my scopes with the flat on the bottom of the turret housing parallel to within .001" across the flat in the top of the rail.

Joe

 

[918v]

The problem is scope base holes are not always drilled correctly and the resulting rail is not 90 degrees to the bore center. Unless you have a flat top receiver or a Surgeon with a built in rail, leveling the crosshairs can involve more than shims.

 

[Pinecone]

Actually the recticle needs to be level with a rifle that is leveled side to side, furthermore, you need to have it level side to side WHEN YOU SHOOT. Otherwise any elevation changes you make will also change horizontal p.o.i.

No, it is only important that the reticle is level when you shoot.

The rifle can be canted, as long as the scope is mounted so that the reticle is level when the rifle is canted.

You should mount the scope such that the reticle is level when you are holding the rifle with your natural point of aim.

 

[Pinecone]

Agreed, gravity don't lie, but for this to work, you need to hold the rifle perfectly plumb as well, and what are you using for a reference suface? Most likely the top of the Picatinny rail.
The feeler method only requires that the receiver and rail are properly machined... has nothing to do with the recoil lug assuming that it is not interfering with the stock; if that is the case, that needs to be fixed before continuing.

If the turrets are not square to the flat on the bottom of the turret housing then you've got even bigger problems... your scope is JUNK and needs to be replaced.

If the reticle is canted relative to the turrets then it needs to be fixed, unless you are only going to use holds or turrets for corrections, but not both.
If the reticle is canted and you are always going to use holds then the reticle needs to be plumb; if you're only going to dial corrections then the turrets need to be plumb/square.

Me, I only buy quality scopes with turrets properly indexed to the turret housing and reticles correctly clocked in, and all of the rails I've mounted have been close enough to square that I am unable to measure any deviation, so I use precision gage pins to mount my scopes with the flat on the bottom of the turret housing parallel to within .001" across the flat in the top of the rail.

Joe

No, the rifle does not need to be level.

You could mount the scope so that it worked properly when the rifle canted 90 degrees.

 

[hermanow]

If the rifle is canted, then the barrel has to be pointed left or right of dead center to hit where you are aiming. The further the target, the further away from dead center it will hit. Draw it out on paper... With a canted rifle, the scope only works properly at the distance it was sighted in.

 

[OptedOut]

I never liked the idea of using feeler gauges when the idea first surfaces years back. I also don't think most recreational shooters really know or shoot consistently enough to worry about rifle cant.

My basic method for getting a scope mounted is by using two machined aluminum bars and two fairly high quality 85mm Starrett machine levels. One bar and level is strapped (via a strong rubber band) to the bottom flat of the scope, the other bar and level is across the top of the rail (counterbalanced with an aluminum 'square').

 

[scudzuki]

No, the rifle does not need to be level.

You could mount the scope so that it worked properly when the rifle canted 90 degrees.

If you did there would be massive windage error at any distance other than the sight in distance.

The line of sight would intersect the bullet path at sight-in distance only; at twice that distance the bullet would have a windage error of the distance between the optical and bore centers to the side opposite the side the scope hangs on.
At 5 times the sight in distance the windage error would be 4 time the distance between the optical and bore centers.
You did take high school geometry, didn't you?

Joe

 

[MoBoost]

If you did there would be massive windage error at any distance other than the sight in distance.

The line of sight would intersect the bullet path at sight-in distance only; at twice that distance the bullet would have a windage error of the distance between the optical and bore centers to the side opposite the side the scope hangs on.
At 5 times the sight in distance the windage error would be 4 time the distance between the optical and bore centers.
You did take high school geometry, didn't you?

Joe

Zero windage at 300. Even if your scope is 1" to the side of the bore at 900 you will experience 3" windage error. Reality is of lesser magnitude - .25" offset with 100 yard zero will have a 2.5" shift at 1000; 300 yard windage zero makes error truly negligible.

Despite the highschool geometry lesson - true vertical crosshair will result in less error then scope true to action but canned to "gravity".

 

[scudzuki]

Zero windage at 300. Even if your scope is 1" to the side of the bore at 900 you will experience 3" windage error. Reality is of lesser magnitude - .25" offset with 100 yard zero will have a 2.5" shift at 1000; 300 yard windage zero makes error truly negligible.

Despite the highschool geometry lesson - true vertical crosshair will result in less error then scope true to action but canned to "gravity".

Bullshit.
Optical center to bore center is on the order of 1-1/2" to 2".
If we pick a number in the center, say 1-3/4" with a 100 yard zero, at 500 yards the windage error would be 7".
Now you are failing at basic arithmetic, your teachers must be proud.
Remember, I am responding to a post suggesting that the scope is alongside the barrel.


Joe

 

[MoBoost]

Bullshit.
Optical center to bore center is on the order of 1-1/2" to 2".
If we pick a number in the center, say 1-3/4" with a 100 yard zero, at 500 yards the windage error would be 7".
Now you are failing at basic arithmetic, your teachers must be proud.
Remember, I am responding to a post suggesting that the scope is alongside the barrel.


Joe

Or you can zero 1.75" windage offset and hold over at all distances. The results will be 100% predictable both in windage and more importantly in elevation - hold over or clicking. The point is the method works even with the most ridiculas sideways gangster style rifle wield.

By the way,

1.75*5 = 8.75 !!!!

We would also accept 8.5 and 9, but not 7.

Now you are failing in basic arithmetic, your teachers must be proud.

Nothing like calling bullshit and arithmetic fail and getting

 

[corym468]

Or you can zero 1.75" windage offset and hold over at all distances. The results will be 100% predictable both in windage and more importantly in elevation - hold over or clicking. The point is the method works even with the most ridiculas sideways gangster style rifle wield.

By the way,

1.75*5 = 8.75 !!!!

We would also accept 8.5 and 9, but not 7.

Now you are failing in basic arithmetic, your teachers must be proud.

Nothing like calling bullshit and arithmetic fail and getting

No he's essentially right. I had to think about this for a second. Your elevation hair(whichever hair is perpendicular with the Earth) needs to be parallel to the vertical travel of the projectile.

It will work properly canted at 90 degree; however, you'll be forced to do a little trig to get the correct windage and elevation correction. I hope you can calculate the sin(theta) & (x)cos(theta) in your head or carry a calculator with you.

 

[JMGlasgow]

I think this thread has run its course. Unless by some small miracle it does happen to get back on topic.

 

[MoBoost]

Ah, shit, his math is correct for 500 years, for some reason I thought he said 600. Sorry I am a dumbass.

SELFPWNED!

 

[Pinecone]

OR, you can take the left/right offset of the optical centerline and the bore, and sight in with that windage offset.

We are not talking about a huge amount of offset.

Say it is even 1"

So sight in, so POI is 1" to the proper side of POA. It will be 1"" off at ALL RANGES.

So if you cannot live with the 1" offset in POI, hold off 1" at any range.

And reality is, for most common amount of cants, the offest will be less than 1/4"

A 10 degree cant would end up with a 0.34" offset

Or about 1 click on mil turrets at 100 yards.