scopes and bubble confusion

[Texas Republic]

I am sure I am making this more difficult than it is, but I am second guessing myself on how to go about this.

I have a Vortex PST with a vortex anti-cant bubble level. I am now mounting it on a Larue QD LT111 scope mount. I have mounted plenty of scopes before by placing a bubble on the rifle and another on the turret. Line the bubbles up and thats it.

What is confusing me is how do I go about mounting it where my crosshairs are absolute level with the anti-cant bubble level? 3 bubble levels? One on turret, one on rifle and the vortex anti-cant bubble?

I tried doing that, but my crosshairs seemed a little canted while looking through the scope with it leveled supposedly. Suggestions?

 

[robert6715]

I am sure lots of folks do it many different ways.For me I level the gun with a level,then plumb the reticle with a plumb bob at 100 yards,then have a buddy level your anti cant device while you hold gun level & plumb.Always keep in mind that if reticle doesn't look plumb when you look thru it you may have been canting the gun all this time & didn't know it.

Rob

 

[The Surgeon]

Thumbs up up to Robert. If you are referencing the reticle with the horizon, even with the gun level, at times the cross hairs will not look level. We are taught that to tell if the reticle is level to just reference it with the horizon. When a anti cant device is placed on the gun is when the shooter finds out how much error there is in that method. I am sure Vortex makes a good ACD but I like U.S. Optics fixed ACD. USO's mounts directly to the optics base removing a lot of installation error.

Like Robert said, the gun must be level and the scope must be level before you can install an ACD on the gun.

 

[Bullet bumper]

The thing to remember is that when you look through the scope in your normal shooting position your eye is in the right position . Not only up and down , left and right but also the correct rotational position.
When you get out of the gun and just peer through the scope again you may see the reticle as out of plumb due mainly to rotation of the eyes position .
Rob is right , plumb the rifle with a level and then set the reticle to look plumb when in your normal shooting position. Then it is just a matter of putting the gun in a clamp of some kind a resetting the action again to plumb and fixing the scope level to the same level .
Some people will have more trouble with this if they suffer from corneal astigmatism of the eye .

 

[LouBoyd]

I am sure I am making this more difficult than it is, but I am second guessing myself on how to go about this.

I have a Vortex PST with a vortex anti-cant bubble level. I am now mounting it on a Larue QD LT111 scope mount. I have mounted plenty of scopes before by placing a bubble on the rifle and another on the turret. Line the bubbles up and thats it.

What is confusing me is how do I go about mounting it where my crosshairs are absolute level with the anti-cant bubble level? 3 bubble levels? One on turret, one on rifle and the vortex anti-cant bubble?

I tried doing that, but my crosshairs seemed a little canted while looking through the scope with it leveled supposedly. Suggestions?

There is no guarantee that the reticle in the scope is not rotated with respect to the direction the target knobs move. In high quality scopes it's usually close to correct but that can slip by QC inspection of cheap scopes. I've seen scope with the reticle over 5 degrees off from the factory.

What's important? If you 're mounting a bubble level and expect it to work right and you have to choose between mounting the scope with the turrets correct or the reticle correct choose having the turrets correct if you plan to use the target turrets with calculated or lookup table drop and windage. Either that or ship the scope back to the manufacurer for repair or replacement. With the bubble in ATD centered the elevation adjustment should track along a vertical line (the gravity vector as measured with a plumb bob). A rotated reticle will not introduce an error as long as you only aim using the center of the crosshair and never use the reticle for offsets

On scopes where the elevation and windage turrets are not used (such as the Horus reticles), it's the reticle which should be aligned to vertical, not the e&w knobs. The reticles have not been detectably rotated on the Horus scopes I own.

 

[Texas Republic]

There is no guarantee that the reticle in the scope is not rotated with respect to the direction the target knobs move. In high quality scopes it's usually close to correct but that can slip by QC inspection of cheap scopes. I've seen scope with the reticle over 5 degrees off from the factory.

What's important? If you 're mounting a bubble level and expect it to work right and you have to choose between mounting the scope with the turrets correct or the reticle correct choose having the turrets correct if you plan to use the target turrets with calculated or lookup table drop and windage. Either that or ship the scope back to the manufacurer for repair or replacement. With the bubble in ATD centered the elevation adjustment should track along a vertical line (the gravity vector as measured with a plumb bob). A rotated reticle will not introduce an error as long as you only aim using the center of the crosshair and never use the reticle for offsets

On scopes where the elevation and windage turrets are not used (such as the Horus reticles), it's the reticle which should be aligned to vertical, not the e&w knobs. The reticles have not been detectably rotated on the Horus scopes I own.

I plan on using the turrets if possible. So you are saying that having the turrets and ACD bubble matching is more important? I am not sure if the level of the reticle and scope differ any, but performing a plumb bob test should verify that right? Line up the string at 100 yards with the reticle and the scope turrets should read level as well right?

 

[Mickey D]

Get a line level. Lowes or Home Depot for around $5.00.
Put your gun in a gun vice. I have a model by MTM. Now place the line level on your scope base. Level the rifle. With the scope mounted in the rings where you can easly turn it in the rings, place the line level on the top scope cap. Level the scope. Check the base. Now tighten the scope screws. Recheck as you go.
When you are through you will have the scope and rifle on the same plane.
I've been shooting since the mid 60's and figured this out about 6 months ago. Old dog thing,I guess...

Robert

 

[robert6715]

I think what Lou is saying is to plumb the scope in the mount, then while holding it plumb crank the elevation turret to make sure it tracks truly plumb.Because if the reticle is installed crooked it will track crooked.You probably need to crank 20-30 moa to see this.

Rob

 

[Mickey D]

I misunderstood the problem.
Have you ever had this happen to a scope? If so what brand.
Robert

 

[Texas Republic]

I misunderstood the problem.
Have you ever had this happen to a scope? If so what brand.
Robert

Its a Vortex Viper PST.

Things have become a little hairy. I sat down tonight and mounted the scope into the Larue QD. I first leveled the scope to the base by placing a bubble on the base and another on the scope turret. I then tightened the rings down with my torque wrench. I next placed the vortex bubble on the scope and matched up the bubbles. All bubbles indicated that they were level..the base, scope turret, and vortex bubble level.

I took it out of the vise and looked through the scope and immediately noticed that the reticle is badly canted. Not a little. A lot. Possibly at the 11 oclock position. I even took the turret cap off and compared the level on the flat head. It matched up the same as the turret.

Soooo, either the reticle is canted inside the scope or the turret doesnt sit perfectly level with the reticle. Am I thinking right here? I plan on going outside in the morning and setting up a weighted string. That way I can line up the reticle and bubble level on the base of my rifle. Once the reticle and base are level, I am going to match those levels to the vortex bubble. Sound right?

Has anyone else with a vortex had this issue?

 

[sp6x6]

I have seen this issue posted before with different scopes.Like Lou said, I have a plumb sharpie line on my shop wall.I have rifle set in gun vise and adjust scope to line.Then as stated you want to check tracking,draw a plumb line at 100 and adjust 20-30 moa and see what it looks like.Some on here purposely cant line for 1000 yrs. spin drift.You can use a collometer to check also

 

[jimbires]

here is a good article . Jim


Reticle Perpendicularity