Leveling a scope question

Kaveman44

Kaveman44

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Apr 2, 2019
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#1
So I have a Short Action Customs scope leveling base. That I mount my scope and spur mount to the base. The base is level as well as the spur mount. I put a plum line about 50 yards out in my yard. Now the scope reticle runs along the plum line but at the top of the reticle it looks like it’s on the center of the line and on the bottom of the reticle it looks like it’s on the left side of the line. Almost like a tiny Bit of an offset . I had to set it there so that when track my scope from zero to all the way, as far as it will track it stays on the line. Would that be more important or should I get the reticle to line up perfectly with the plum bob? Thanks Jimmy

Also, this is a brand tangent Theda 7 x 35, I would hope it’s tracking
 
#2
Kaveman44 said:
So I have a Short Action Customs scope leveling base. That I mount my scope and spur mount to the base. The base is level as well as the spur mount. I put a plum line about 50 yards out in my yard. Now the scope reticle runs along the plum line but at the top of the reticle it looks like it’s on the center of the line and on the bottom of the reticle it looks like it’s on the left side of the line. Almost like a tiny Bit of an offset . I had to set it there so that when track my scope from zero to all the way, as far as it will track it stays on the line. Would that be more important or should I get the reticle to line up perfectly with the plum bob? Thanks Jimmy

Also, this is a brand tangent Theda 7 x 35, I would hope it’s tracking
Click to expand...
Can I see a picture of how you have the scope level setup? Also try putting the plumb bob closer. No need for it to be 50 yards away
 
#3
I took everything down for the night, but I will send you a picture of how I have it set up. I think the reason I had it set at 50 yards is because I sit on my patio in the shade and I put my plumbob hanging off my Archery target out my yard. But I’ll just put both of them in the patio.
 
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#5
I did checked the diopter and parallax

The scope base is leveled from front to back and side to side
 

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#6
What did you put the level on when leveling the scope?

I think it would be more important to have the reticle level, as long as the reticle stays on the line when you dial the turrets. If it tracks weird, the reticle is off from the turret. I know it's like comparing apples to raisins, but my Razor HD LHT is off a couple degrees when the turret is level (turret cap removed). I lined the reticle up with a plumb bob and dialed the scope as far as it would go both ways to make sure it tracked true and it did, so I ignored that the turret wasn't truly level.
 
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#7
So one thing I should say is the line I’m using is a very small line. And before I start tracking it, it’ll be on the center of the line and by the time I’m done dialing my scope all the way down it’ll be touching the right side of the line.
 
#8
Kaveman44 said:
So one thing I should say is the line I’m using is a very small line. And before I start tracking it, it’ll be on the center of the line and by the time I’m done dialing my scope all the way down it’ll be touching the right side of the line.
Click to expand...
Don’t use the plumb bob to determine tracking. You need to use an actual tall target test for that as far as a plumbob it doesn’t have to be thick, but it shouldn’t be very thin either. I think I have mine set up about 15 feet away from the front of the scope.
 
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#9
Sounds like you may either have some user setup error and/or the reticle may be slightly canted.

I use a calibrated target, and I’ve seen many reticles with a slight cant, and some that have been imperceptible. Most have been 1 degree or less, but some cheapo chinesium I’ve seen have been pretty wild.
 
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#10
Kaveman44 said:
I put a plum line about 50 yards out in my yard. Now the scope reticle runs along the plum line but at the top of the reticle it looks like it’s on the center of the line and on the bottom of the reticle it looks like it’s on the left side of the line. Almost like a tiny Bit of an offset . I had to set it there so that when track my scope from zero to all the way, as far as it will track it stays on the line. Would that be more important or should I get the reticle to line up perfectly with the plum bob?
Click to expand...

I'd think about what that means for downrange performance from a practical perspective. If you're dialing up 10 mils to start to see the reticle move from one side of a thin line to the other, that's maybe a 0.05 mil offset? That would mean when you dial 10 mils for a ~1100 or 1200 yard shot, your point of aim will be slightly to the side by a half a tenth. I would think that's going to get completely lost in the noise of wind or even how exactly precise you level the gun at the time you're shooting.

If you wanted to be *ultra* precise, you could set the bubble level to align perfectly with the tracking as you dial elevation, and let the reticle be ever so slightly canted. Odds are that the most you'll hold over when shooting is maybe 5 mils, where you would probably dial elevation for a longer range shot.

I wouldn't be concerned that it's a defect with the scope, that sounds to me to be well within reasonable manufacturing tolerances.
 
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#11
Sheldon N said:
I'd think about what that means for downrange performance from a practical perspective. If you're dialing up 10 mils to start to see the reticle move from one side of a thin line to the other, that's maybe a 0.05 mil offset? That would mean when you dial 10 mils for a ~1100 or 1200 yard shot, your point of aim will be slightly to the side by a half a tenth. I would think that's going to get completely lost in the noise of wind or even how exactly precise you level the gun at the time you're shooting.

If you wanted to be *ultra* precise, you could set the bubble level to align perfectly with the tracking as you dial elevation, and let the reticle be ever so slightly canted. Odds are that the most you'll hold over when shooting is maybe 5 mils, where you would probably dial elevation for a longer range shot.

I wouldn't be concerned that it's a defect with the scope, that sounds to me to be well within reasonable manufacturing tolerances.
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i was thinking how much of a difference would that be at distance. Im sure I can't shoot the difference, lol. I'm going to align the reticle and do a tall target just to verify. on my last scope I just aligned the reticle, and it worked out great
 
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#12
A scope can be leveled perfectly to the rifle, but still be canted one way or the other when you mount the rifle to your shoulder.

Having the scope level to the mount/base/rifle is less important than having the scope level to how your shoot the rifle.

Assuming the scope/reticle is mounted level to the rifle; close your eyes and mount your rifle comfortably to you shoulder. Is the reticle level? If not, use what adjustments you have on your stock to level the rifle to your way of shooting. Mount the rifle again. Is the reticle level? If not, you may need to adjust the scope away from “level to the rifle,” so that it is level to how you shoot.
 
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#13
HMRamateur said:
What did you put the level on when leveling the scope?
Click to expand...
This has always been a tricky thing for me with my TT scopes. The turret's tool-less adjust mechanism means that the top of the turret isn't level and there's no flat there. And the bottom of the turret housing is also not flat since there's a door/cap there from manufacturing where they insert mechanisms. So... there really isn't a true "flat" plane anywhere on the scope with which to reference.

Best you can do is make sure your ring/mount/rifle is level and then align your reticle to that plane using a plumb line. Trying to use feeler gauges, playing cards, or bubble levels to mount is fruitless.
 
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#18
FWIW I've always had better results using a plumb bob at 50 or 100 yards vs close. I used to do it at like 20 feet but did a couple tall target tests and realized I had some error. I seem to be able to get it much better farther out. The discrepancy between your reticle and tracking is a tough one, might be in the scope might be some movement in your set up. I'd either forget about it because it sounds negligible or shoot a tall target test and see where you end up.
 
#20
Taylorbok said:
FWIW I've always had better results using a plumb bob at 50 or 100 yards vs close. I used to do it at like 20 feet but did a couple tall target tests and realized I had some error. I seem to be able to get it much better farther out. The discrepancy between your reticle and tracking is a tough one, might be in the scope might be some movement in your set up. I'd either forget about it because it sounds negligible or shoot a tall target test and see where you end up.
Click to expand...
I'm going to have to shoot a tall target test
 
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#21
Kaveman44 said:
I'm going to have to shoot a tall target test
Click to expand...
I wouldn't shoot a tall target to diagnose/confirm what sounds to be a very small amount of reticle cant. Even a world record setting rifle/shooter is going to have a hard time confirming a small partial degree of cant. How thick is the string on your plumb bob and how many many mils of travel does it take for you to perceive the reticle "veering" to one side? As an example if you dial 20 mils of elevation and your string is 1/8" in diameter, we are talking ~1/5th of a degree of reticle cant with a plumb bob set at 50 yards. That will be completely lost in the noise of live fire. If we are talking 1+ degrees of cant, you could see that depending on equipment & skill, but you'll still be better off confirming without live fire.

Also, if your tripod is sturdy enough, properly weighted down, parallax is resolved, etc., it is very repeatable to run a tracking test and check for reticle cant.
 
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#22
Secant said:
I wouldn't shoot a tall target to diagnose/confirm what sounds to be a very small amount of reticle cant. Even a world record setting rifle/shooter is going to have a hard time confirming a small partial degree of cant. How thick is the string on your plumb bob and how many many mils of travel does it take for you to perceive the reticle "veering" to one side? As an example if you dial 20 mils of elevation and your string is 1/8" in diameter, we are talking ~1/5th of a degree of reticle cant with a plumb bob set at 50 yards. That will be completely lost in the noise of live fire. If we are talking 1+ degrees of cant, you could see that depending on equipment & skill, but you'll still be better off confirming without live fire.

Also, if your tripod is sturdy enough, properly weighted down, parallax is resolved, etc., it is very repeatable to run a tracking test and check for reticle cant.
Click to expand...
There's literally no harm in shooting a tall target test.
 
#23
Taylorbok said:
There's literally no harm in shooting a tall target test.
Click to expand...
Other than it adds unnecessary variables and could cause you to chase your tail. How well is the scope actually zero’d? With how many rounds? What’s the radial SDs from the ‘system’ and based on how many rounds? How tall is the tall target? How many rounds from you & your equipment are truly required? Etc.

If that’s the best method available to you, it’s fine, as long as you understand that you are only able to resolve relatively large tracking errors and/or fairly significant reticle cants, and you’ll need to parse out what’s what. Eliminating the live fire component is just a faster, more accurate/precise, and more economical way to evaluate is all I’m saying.
 
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#24
My process is a little time-consuming but it has served me well.

I always adjust the scope cant to a near-in plumb line or any other verified level surface at a greater distance. However, I do it using a Badger dead level and then move on to fine-tune it after I shoulder the rifle.

I shoot a 4X5 set at 100 yards and each 5-shot group needs to be < 0.5 MOA. I never will shoot a tall target unless the rifle is zeroed properly. The Tall target has to be mounted to a rigid surface and it has to be level or it won't provide meaningful information. The tall target should give you at least 10 mils of adjustment at 100 yards. I shoot three shots at each mil marker. I follow with a box test on the same target. The box test ensures the windage turret is also tracking true and the elevation adjustment is repeatable.

YMMV
 
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#25
I just use a leveling tool to level the scope to the base, put the base on the rifle, tighten it down, go shoot and be happy. I trust my tools until they fail me, then i check what wrong, in 45 years of shooting it has worked for me. YMMV
 
#26
oldrifleman said:
I just use a leveling tool to level the scope to the base, put the base on the rifle, tighten it down, go shoot and be happy. I trust my tools until they fail me, then i check what wrong, in 45 years of shooting it has worked for me. YMMV
Click to expand...
Depending on the distance you shoot this might work fine. If you regularly shoot 1mile + it's good to be certain you don't have a cant error in your reticle/ turrets.
 
#28
oldrifleman said:
I just use a leveling tool to level the scope to the base, put the base on the rifle, tighten it down, go shoot and be happy. I trust my tools until they fail me, then i check what wrong, in 45 years of shooting it has worked for me. YMMV
Click to expand...
Do you mean one piece mount going on a picatinny ?
 
#29
This is the line I use, it’s Archery D Loop material, it is a 16th of an inch thick. So I am running my radical parallel with the line and I’m gonna shoot it. When I start with it in the middle of the line I dial 28 mils up and it’s still touching the line.
 

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#31
_Windrider_ said:
Don’t use the plumb bob to determine tracking. You need to use an actual tall target test for that as far as a plumbob it doesn’t have to be thick, but it shouldn’t be very thin either. I think I have mine set up about 15 feet away from the front of the scope.
Click to expand...
What scope is letting you focus on a plumb bob line at 15’?
 
#32
@Lowlight has written that unless the shooter already knows he cants his scope in the rings to compensate for how he shoulders the rifle, they level their student’s scope mounts, mount the scope, and then plumb the reticles to a known plumb object.

It doesn’t matter if your turret or scope base is level to whatever. All that matters is that the reticle is plumb to gravity.

1718764556052.png


Link to lowlight’s long version in post below:
www.snipershide.com

Gunsmithing - Scope level to a rifle

Reading over this resurrected thread got me thinking. And that's not always the best place for me. It's obvious that the only thing that matters is that the reticle is level when the shot is taken. The rifle could be canted a few degrees and as long as it was zeroed in that position with a level...
www.snipershide.com www.snipershide.com
 
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#33
I have known square objects that I level to at home.

With that said, I have mounted scopes in a hotel room right before leaving for a match. Since I usually fly with a disassembled rifle.

I use a flash light through the objective, a piece of weighted dental floss where the weight sits in a cup of water to prevent movement. It has worked well in as little as 5-10 feet of moving room.

It sounds like you're good to go, I wouldn't stress too much about it.
 
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#35
I prefer the Arisaka Optic Leveler tool to start. It levels the scope based on the turrets flat surface (bottom). Adjustable turrets aren't good for balancing levels.

I've had a lot of scope leveling tools. The Badger, Short Action Customs, EXD, Arisaka etc. use whatever gives you confidence then confirm with real world data on targets.
 
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#36
USMC22 said:
I prefer the Arisaka Optic Leveler tool to start. It levels the scope based on the turrets flat surface (bottom). Adjustable turrets aren't good for balancing levels.
Click to expand...

See above. TT has no true flat on the bottom AND... that Arisaka tool doesn't fit under most normal-height rings for a TT. I've tried using one and there just isn't enough room unless your scope is mounted like a lifted 4x4.
 
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#38
alnkal00 said:
This vid and it shows a fix for your erector housing bottom not being flat
Also an LRA Send It makes things easier

Click to expand...

I'm not buying into this. . . leveling to a canted rail is no different than a 0 moa rail.

His theory of "dialing windage into elevation" because of built in rail cant doesn't add up.

If a reticle is plumb to gravity than it'll be plumb on a 0 or 30 moa if the rifle and bore axis are aligned.

When something goes from level to NOT LEVEL when changing the angle thats a 3rd axis issue, i.e. the receiver/rail is not in straight line with the bore / scope.
 
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