I have always mounted my scopes to my rifles by leveling the action and then using a plumb bob to get the crosshair lined up. Has always worked for me. I just got a Vortex PST and want to be able to dial shots with it. I mounted it per Vortex instructions, level the action and then level the scope by putting a bubble on the turret cap. The problem is, when I level the scope like this the cross hairs are canted to the left significantly. When I plumb bob the cross hair, then the turret cap is not level. If I set the cross hair level like I always have, will I have trouble dialing shots since the turret is not aligned?? Is there something wrong with my scope??(brand new) Am I doing something wrong?? Confused and frustrated...someone please give me a hand.
Mounting help.
- Thread starter HUNTNMT
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Bigcat_hunter
Well-Known Member
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My guess is that the turret cap is not machined to such tight tolerances that it perfectly matches the turret mechanism. Having the action level is not that important. Having the reticle level is. Set the scope and action close to the same plane. Get a scope level that will be permanently mounted to the scope. Set up a level at the range and set the reticle and scope level to that. Having the reticle level to the earth is much more important than having the action and the scope on the same plane.
I don't have the data to prove it but from my understanding and (somewhat limited) experience to 1000 yards, a slight cant in the scope won't make a difference.
bruce_ventura
Well-Known Member
I agree with bill113 about needing to level the scope, not the action. I do a lot of scope installations because I run scope clinics at two local shooting ranges every month.
It is not uncommon for me to see reticles misaligned to the turret axis by up to three degrees. In this case where you're dialing elevation, the elevation turret axis must be plumb. If you're holding off elevation using a BDC or milling reticle, then the vertical reticle line should be plumb.
For long range shots you absolutely need a properly aligned anti-cant indicator to hold the scope level during the shot.
For 1,000 yd shots even a small cant of 2 degrees can produce a significant aiming error. I recommend reducing the alignment error below 1 degree. To do that, you need levels that are accurate to within 0.5 degree.
Injection molded plastic leveling tools with snap-in spirit levels or sloppy moving parts are not accurate enough for long range. I typically see errors of about 2 degrees. The Wheeler molded plastic levels can be lapped to make them more accurate. The Segway molded plastic tool cannot be made more accurate because the sliding bar flexes and the fit in the plastic part gets looser with time, causing the bar to be out of alignment with the spirit level.
Another windage aiming error can occur in long range shots when 1) the vertical turret axis is not aligned with the center of the rifle bore, and 2) the rifle is zeroed at short range, like 100 yds, and then the elevation is adjusted for a long range shot. If the vertical turret axis is not aligned with the bore, then the windage error will increase as the elevation is increased. This error can also occur when holding off elevation. It can be eliminated by properly aligning the scope with the bore.
To remove this range-dependent error, you need either the EXD tool, or the RingTrue Reticle Alignment Tool that HighPowerOptics sells. The spirit level on the RingTrue tool is guaranteed accurate to within +/- 0.5 degree, so you don't need any other spirit levels.
http://www.highpoweroptics.com/ringtrue™-reticle-alignment-tool-p-16566.html
It is not uncommon for me to see reticles misaligned to the turret axis by up to three degrees. In this case where you're dialing elevation, the elevation turret axis must be plumb. If you're holding off elevation using a BDC or milling reticle, then the vertical reticle line should be plumb.
For long range shots you absolutely need a properly aligned anti-cant indicator to hold the scope level during the shot.
For 1,000 yd shots even a small cant of 2 degrees can produce a significant aiming error. I recommend reducing the alignment error below 1 degree. To do that, you need levels that are accurate to within 0.5 degree.
Injection molded plastic leveling tools with snap-in spirit levels or sloppy moving parts are not accurate enough for long range. I typically see errors of about 2 degrees. The Wheeler molded plastic levels can be lapped to make them more accurate. The Segway molded plastic tool cannot be made more accurate because the sliding bar flexes and the fit in the plastic part gets looser with time, causing the bar to be out of alignment with the spirit level.
Another windage aiming error can occur in long range shots when 1) the vertical turret axis is not aligned with the center of the rifle bore, and 2) the rifle is zeroed at short range, like 100 yds, and then the elevation is adjusted for a long range shot. If the vertical turret axis is not aligned with the bore, then the windage error will increase as the elevation is increased. This error can also occur when holding off elevation. It can be eliminated by properly aligning the scope with the bore.
To remove this range-dependent error, you need either the EXD tool, or the RingTrue Reticle Alignment Tool that HighPowerOptics sells. The spirit level on the RingTrue tool is guaranteed accurate to within +/- 0.5 degree, so you don't need any other spirit levels.
http://www.highpoweroptics.com/ringtrue™-reticle-alignment-tool-p-16566.html
Iclimb
Well-Known Member
Do you have a video of the use of the reticle alignment tool being used? I can't understand a few things about it. I've read the instructions etc. and it can't seem to get it.
Do you level the rifle first, then put the ringtrue on and hold it level, then index the reticle to that? Then I see the level being used on the turret?
Do you notice any variants due to the inside bore being different from the outside of the barrel? Does that make sense?
It is best to test it at say 100 yrd. Draw a 4 foot plumb line on paper, then 100 or 200 whatever your zero is. Then dial up and aim same and see that hits track on line as you move impact up.
bruce_ventura
Well-Known Member
QUOTE="Iclimb;892067"] Do you have a video of the use of the reticle alignment tool being used? I can't understand a few things about it. I've read the instructions etc. and it can't seem to get it. Do you level the rifle first, then put the ringtrue on and hold it level, then index the reticle to that? Then I see the level being used on the turret? Do you notice any variants due to the inside bore being different from the outside of the barrel? Does that make sense?[/QUOTE]
I don't have a video yet. It's on the list when we start video production again in Jan. PM your phone number to me and I'll call you. Include a good time to call.
Using the RingTrue tool is a two- step process:
1) Align the RingTrue tool to the barrel and scope objective bell. The double stock tape on the back will hold the tool in place against the objective bell. Rotate the rifle to level the tool. Hold the rifle in that position (any type of vise will do).
This first step does not require ultrahigh precision. Errors due to the bore not being perfectly centered in the barrel are negligible.
2) Make sure the ring screws are loose so that the scope rotates easily in the rings. Remove the RingTrue tool and hold it upside down against a flat surface on the turret housing (turret cap, flat side of housing, etc.). Rotate the scope (not the rifle) to level the tool. Then tighten the ring screws.
To level the reticle instead of the turret axis, set up a plumb line 50 ft away and look through the scope. You can use a plumb bob or draw a straight line on a sheet of appear and use the RingTrue tool to plumb the line while you attach the sheet to a wall.
If you have an anti-cant device, install it now, while the scope is still level. This is where you should take care to align everything accurately. The spirit level on the RingTrue tool is very accurate (less than +/- 30 MOA of error).
I don't have a video yet. It's on the list when we start video production again in Jan. PM your phone number to me and I'll call you. Include a good time to call.
Using the RingTrue tool is a two- step process:
1) Align the RingTrue tool to the barrel and scope objective bell. The double stock tape on the back will hold the tool in place against the objective bell. Rotate the rifle to level the tool. Hold the rifle in that position (any type of vise will do).
This first step does not require ultrahigh precision. Errors due to the bore not being perfectly centered in the barrel are negligible.
2) Make sure the ring screws are loose so that the scope rotates easily in the rings. Remove the RingTrue tool and hold it upside down against a flat surface on the turret housing (turret cap, flat side of housing, etc.). Rotate the scope (not the rifle) to level the tool. Then tighten the ring screws.
To level the reticle instead of the turret axis, set up a plumb line 50 ft away and look through the scope. You can use a plumb bob or draw a straight line on a sheet of appear and use the RingTrue tool to plumb the line while you attach the sheet to a wall.
If you have an anti-cant device, install it now, while the scope is still level. This is where you should take care to align everything accurately. The spirit level on the RingTrue tool is very accurate (less than +/- 30 MOA of error).
Iclimb
Well-Known Member
Thanks, it is the first step that has me confused. This is an extreme example but you could have the tool completely cocked to the side say 30° tape to the bell rotate your rifle so this thing shows level but now you have a canted action. I understand your thoughts on whether that matters or not. The rest of the tool seems great I think I might get one to use on my action slides for leveling
bruce_ventura
Well-Known Member
The RingTrue alignment tool has a V-notch on the bottom that aligns to the barrel. It also has a series of parallel lines printed on the face. You set the tool on the barrel and rotate it so that the objective bell is centered between the parallel lines. Press the tool against the objective bell so that the tape sticks to it. Rotate the rifle to get the alignment tool plumb, then secure the rifle in that position. Then proceed to step two.
Iclimb
Well-Known Member
Ah, you should publish "the lines" step. The v notch can be rotated infinitely on the barrel (if it didn't hit the stock) is what had me wondering in what world that would be accurate. But makes more sense with the lines now. I still prefer to level my action from a known spot.
Cool thanks.
