Question about shimming scope rings

tpcollins · March 10, 2017, 09:40 PM

I have a crossbow scope with 92 MOA travel - 46 MOA each way from the center. But it is lined up right now with only 36 clicks available to the left and 55 clicks to the right, which messes up the farthest yardage using the elevation turret as the erector tube may be bumping the inside of the scope tube (that's what Vortex said).

I want to get it closer to the center position by laterally shimming the rear ring. But doing that could put stress on the tube sides since they're not concentric (probably aren't now as it is).

Is this ok to do on 30mm tube or must they be lapped now because of the minor misalignment? Thanks.

Mobuck · March 10, 2017, 10:04 PM

I don't think this will be an issue since it appears you're only about 1/3 of the clicks from center.

243winxb · March 10, 2017, 11:24 PM

Cut 2 shims from a soda can and stick them in there. Each shim is about .004" thick.

Keep shims on one side of the ring split. If split horizontal, top or bottom of the ring.

NoSecondBest · March 11, 2017, 12:20 AM

Makes no sense. If you have adjustment left, you have no need to shim. Also, left and right have no bearing on how far you can shoot, up and down does that. Suggestion: get a xbow scope with mil dots or stadia lines in it. Most xbow scopes are that way to begin with.

Blindstitch · March 11, 2017, 01:19 AM

10 clicks isn't anything to care about. Set it and forget it.
4 clicks equals an inch at 100 yards. 16 clicks equals an inch at 25 yards.

tpcollins · March 11, 2017, 09:27 AM

Evidently I deleted the first part when I edited it but the crossbow scope is 1 MOA per click. So with 46 clicks from the center position, the 9 clicks from it is about 20% of the travel - not sure if it's relevant or not but when I use the elevation turret for yardages compared to the reticle, the poi moves to the right as I indicated.

Where others are saying to put the shims is confusing. Are you suggesting to put it inside the scope ring next to the scope tube? I was thinking of bending some thin brass stock at right angles and put it between the outside edge of picatinny rail and the inside of the fixed section of the mount that clamps against the picatinny.

My concern is how much shimming can I do before the shimmed and unshimmed rings compromise the scope's tube?

243winxb · March 11, 2017, 09:31 AM

Shim the mount first , if possible. Its best.

Shim inside the rings as the 2nd choice.

NoSecondBest · March 11, 2017, 11:07 AM

Quote:

Evidently I deleted the first part when I edited it but the crossbow scope is 1 MOA per click. So with 46 clicks from the center position, the 9 clicks from it is about 20% of the travel - not sure if it's relevant or not but when I use the elevation turret for yardages compared to the reticle, the poi moves to the right as I indicated.

If you're moving the "elevation" turret and the scope's moving to the right, you have the scope mounted 90 degrees off. You've put the elevation turret on the side and the R-L turret on top.

Blindstitch · March 11, 2017, 04:33 PM

I think you need to post up a picture of your rig. What is it exactly. I shoot a Barnett Veloci-Raptor and don't trust any store with setting things up for me.

I've seen to many cockeyed adjustments. Remove the scope, remove the rings, remove the base if it comes off. Then place the crossbow in a gunvise, arrangement of pillows or something to keep it steady and reassemble keeping things level and retest.

Your POI can also move if you're holding the crossbow wrong. Cocked a bit to one side or the other will throw you off as you move farther away from the target.

tpcollins · March 11, 2017, 06:07 PM

Here's my Scorpyd Ventilator with the Vortex XBR scope. It has a scope level as well to keep it horizontal when shooting. The one problem with Scorpyd is their short crappy scope rails so I'm hostage to extended ring mounts. I tried several brands but the crappy Hawke mounts were what I liked as far as height.

The XBR scope is basically the Vortex Viper Series with a different recticle in MOA and 1 MOA per click. With the article in equidistant MOA, it doesn't align with crossbow trajectories very well. But with it on 4x, and keeping the trajectory apex between the 50 & 60 yard chevrons, I can use it to shoot 31-41-50-59-68 yards very well.

But I can also turn up the magnification and use the turret for the yardages as well. The end of the turret up is 70 yards, but because the windage is 20% off center, the erector tube is hitting the side of the scope tube when the elevation maxes out and it skews the poi to the right.

I think it's the cheapass Hawke rings. I may try to take the rear ring and turn it around 180 degrees to see it it gets closer to the scope's center position. Otherwise I'll spend some money for a better mounting system.

Blindstitch · March 11, 2017, 07:05 PM

You do seem to have a lot going on there. Have you tried asking people over on the Crossbow Nation forum. They have a lot of knowledgeable guys there and some are prostaff to certain crossbow brands.

Seems like there has to be an easy way to solve your problem and have the level, top rail and whatever is under your zoom ring on the scope. That has to be the longest crossbow scope i've seen.

tpcollins · March 11, 2017, 10:27 PM

Quote:

You do seem to have a lot going on there. Have you tried asking people over on the Crossbow Nation forum. They have a lot of knowledgeable guys there and some are prostaff to certain crossbow brands.

Seems like there has to be an easy way to solve your problem and have the level, top rail and whatever is under your zoom ring on the scope. That has to be the longest crossbow scope i've seen.

My original question was:

Quote:

I want to get it closer to the center position by laterally shimming the rear ring. But doing that could put stress on the tube sides since they're not concentric (probably aren't now as it is).

Is this ok to do on 30mm tube or must they be lapped now because of the minor misalignment? Thanks.

I would have thought guys from the Smithy forum of the Firing Line would have more expertise in answering my question on the subject but maybe I was wrong - my bad.

Blindstitch · March 13, 2017, 02:58 AM

When you say

Quote:

31-41-50-59-68 yards very well.

Are you saying that the cross-airs line up perfectly to shoot those yardages and then when you hit 70 yards the scope jumps off for POI?

tpcollins · March 13, 2017, 07:57 AM

Quote:

When you say

Quote:
31-41-50-59-68 yards very well.

Are you saying that the cross-airs line up perfectly to shoot those yardages and then when you hit 70 yards the scope jumps off for POI?

Quote:

The XBR scope is basically the Vortex Viper Series with a different recticle in MOA and 1 MOA per click. With the reticle in equidistant MOA, it doesn't align with crossbow trajectories very well. But with it on 4x, and keeping the trajectory apex between the 50 & 60 yard chevrons, I can use it to shoot 31-41-50-59-68 yards very well.

But I can also turn up the magnification and use the turret for the yardages as well. The end of the turret up is 70 yards, but because the windage is 20% off center, the erector tube is hitting the side of the scope tube when the elevation maxes out and it skews the poi to the right.

I'm pretty sure I referenced using the scope's reticle to shoot 31-68 yards very well, and I'm pretty sure I referenced using the turret to dial up the various yardages with the issue being at the end of the travel which is 70 yards.

But all of these questions are irrelevant because nobody addressed my original concern. Thanks for the help, I'll figure it out.

NoSecondBest · March 13, 2017, 08:34 AM

I suggest you visit archerytalk.com and go to the crossbow sub-forum. You'll learn a bit about scopes and how they're used on crossbows. From reading your OP and following the responses it sounds to me like you don't understand how to properly use/mount/adjust a scope and you don't understand how they're used on crossbows. No offense intended, but you won't get a good answer here until you yourself have a better understanding. If's difficult for other people to answer your questions if you don't understand their answers. Good luck with this.

Blindstitch · March 13, 2017, 10:43 AM

Quote:

But all of these questions are irrelevant because nobody addressed my original concern. Thanks for the help, I'll figure it out.

Shim the scope inside the rings with thin metal. No need to lap.

tpcollins · March 13, 2017, 11:12 AM

Quote:

Shim the scope inside the rings with thin metal. No need to lap.

In lieu of shimming between the ring base and the scope rail? I'm not sure how much room - if any - there is between the inside of the 30mm rings and the scope's tube?

NoSecondBest - I am a member of ArcheryTalk/CrossbowTalk and Crossbow Nation already. It is not a crossbow question - it's a shimming a scope question whether it's on a crossbow, rifle, BB gun or a pea shooter. Thanks for all the help.

If there's a way to delete this post then I'm good.

Blindstitch · March 13, 2017, 12:36 PM

There should be enough room to shim what you need. Pieces of pop cans make great shims. Shouldn't take much.

Were the Crossbow Nation people not willing to help? Someone has to have your same setup there.

tpcollins · March 13, 2017, 02:03 PM

Quote:

There should be enough room to shim what you need. Pieces of pop cans make great shims. Shouldn't take much.

Were the Crossbow Nation people not willing to help? Someone has to have your same setup there.

I didn't even ask - since it was a scope shimming question, I just made the assumption that the guys here on the gunsmith sub-forum of The Firing Line were a helluva lot more competent on scopes and mounts than some bowhunters, irregardless what it is mounted on.

If rotating the rear scope ring doesn't get the scope back to the center position for horizontal, I'm going to get the Nikon M-Series XR mount with the 20 MOA slope, as it appears to have "windage adjustable" mounting plates on each side.

With that mount I can just center the scope and use the side mounts to adjust the horizontal until the POI is dead nuts.

Blindstitch · March 13, 2017, 03:42 PM

That XR mount looks like a good solution. Should eliminate any misalignment of two piece mounts.

**Unclenick** · March 14, 2017, 10:32 AM

Tpcolins,

You are correct that you can ring (indent and possibly spoil optics alignment) scope tubes by having one ring off the axis of the other as by shimming up only the rear ring of a horizontal ring set. You really want to shim the whole base. Otherwise, use a tapered long range scope base. Another approach is to use the Burris XTR rings with pivoting ball-and-socket ring inserts that can be shimmed without stressing the scope tube because the ring insides turn with it. Barret has another solution.

I went through all your posts and corrected your tags. Here's what went wrong: You were omitting the [ that must begin the close quote tag for the quote tag pair to work.

You had:
[quote]content/quote], which produces itself: [quote]content/quote]

It should have been:
[quote]content[/quote], Which produces:

Quote:

content

You were also geting the opening bold tag inside the opening quote tag.

You had:
[quote[b]]content[/b]/quote], which produces:[quote]content/quote]

It should be:
[quote][b]content[/b][/quote], which produces:

Quote:

content

The only inclusion that goes inside the quote tag brackets is =name, which credits the original poster as follows:

[quote=bigmouth]content[/quote]

Will produce:

Quote:

Originally Posted by bigmouth

content

tpcollins · March 16, 2017, 07:55 AM

Thanks Unclenick. Since there's not a "reply with quote" feature, the only was I could figure out how was to "copy, then click on the "insert image" icon, and then hit paste with the cursor blinking in between the two - "quote l quote". I'll have to practice more.

I have used the Burris Signature rings before and tried them the first time on this crossbow but Scorpyd decided to put a short scope rail on their crossbows so I need extension type rings/mount as you can see in post #10.

At least you addressed my concern. Thanks.

tpcollins · March 16, 2017, 08:05 AM

[QUOTE]At least you addressed my concern. Thanks./QUOTE]

When I go to insert between the ][, for whatever reason the 2nd [ gets eliminated when I paste. Here's what it looks like if I manually add it back.

Quote:

Originally Posted by tpcolins

At least you addressed my concern. Thanks.

Got it!

**Unclenick** · March 16, 2017, 01:19 PM

That's curious. I tried it several times, and it's not happening with me. Must be something about your system. But at least you now know why it wasn't working.

We turned off the quote feature here because people don't edit the quoted portions down to the sentences they want to respond to. They leave giant passages and photos all intact, which uses up a lot of storage space and bandwidth and nobody wants to reread it all anyway.

tpcollins · March 18, 2017, 10:52 AM

Quote:

Originally Posted by Unclenick

We turned off the quote feature here because people don't edit the quoted portions down to the sentences they want to respond to..

I always try to trim the quotes down.

Thanks.

March 11, 2017, 09:27 AM	#6
tpcollins Senior Member Join Date: February 18, 2009 Location: SE Michigan Posts: 558	Evidently I deleted the first part when I edited it but the crossbow scope is 1 MOA per click. So with 46 clicks from the center position, the 9 clicks from it is about 20% of the travel - not sure if it's relevant or not but when I use the elevation turret for yardages compared to the reticle, the poi moves to the right as I indicated. Where others are saying to put the shims is confusing. Are you suggesting to put it inside the scope ring next to the scope tube? I was thinking of bending some thin brass stock at right angles and put it between the outside edge of picatinny rail and the inside of the fixed section of the mount that clamps against the picatinny. My concern is how much shimming can I do before the shimmed and unshimmed rings compromise the scope's tube? __________________ What direction did that last shot at Kennedy come from?

March 16, 2017, 07:55 AM	#22
tpcollins Senior Member Join Date: February 18, 2009 Location: SE Michigan Posts: 558	Thanks Unclenick. Since there's not a "reply with quote" feature, the only was I could figure out how was to "copy, then click on the "insert image" icon, and then hit paste with the cursor blinking in between the two - "quote l quote". I'll have to practice more. I have used the Burris Signature rings before and tried them the first time on this crossbow but Scorpyd decided to put a short scope rail on their crossbows so I need extension type rings/mount as you can see in post #10. At least you addressed my concern. Thanks. __________________ What direction did that last shot at Kennedy come from? Last edited by tpcollins; March 16, 2017 at 08:01 AM.

March 16, 2017, 01:19 PM	#24
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	That's curious. I tried it several times, and it's not happening with me. Must be something about your system. But at least you now know why it wasn't working. We turned off the quote feature here because people don't edit the quoted portions down to the sentences they want to respond to. They leave giant passages and photos all intact, which uses up a lot of storage space and bandwidth and nobody wants to reread it all anyway. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

March 10, 2017, 09:40 PM	#1
tpcollins Senior Member Join Date: February 18, 2009 Location: SE Michigan Posts: 558	Question about shimming scope rings I have a crossbow scope with 92 MOA travel - 46 MOA each way from the center. But it is lined up right now with only 36 clicks available to the left and 55 clicks to the right, which messes up the farthest yardage using the elevation turret as the erector tube may be bumping the inside of the scope tube (that's what Vortex said). I want to get it closer to the center position by laterally shimming the rear ring. But doing that could put stress on the tube sides since they're not concentric (probably aren't now as it is). Is this ok to do on 30mm tube or must they be lapped now because of the minor misalignment? Thanks. __________________ What direction did that last shot at Kennedy come from?

March 10, 2017, 10:04 PM	#2
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	I don't think this will be an issue since it appears you're only about 1/3 of the clicks from center.

March 10, 2017, 11:24 PM	#3
243winxb Senior Member Join Date: July 26, 2011 Location: USA Posts: 1,730	Cut 2 shims from a soda can and stick them in there. Each shim is about .004" thick. Keep shims on one side of the ring split. If split horizontal, top or bottom of the ring.

March 11, 2017, 12:20 AM	#4
NoSecondBest Senior Member Join Date: December 7, 2009 Location: Western New York Posts: 2,736	Makes no sense. If you have adjustment left, you have no need to shim. Also, left and right have no bearing on how far you can shoot, up and down does that. Suggestion: get a xbow scope with mil dots or stadia lines in it. Most xbow scopes are that way to begin with.

March 11, 2017, 01:19 AM	#5
Blindstitch Senior Member Join Date: April 14, 2013 Location: Milwaukee, Wisconsin Posts: 2,693	10 clicks isn't anything to care about. Set it and forget it. 4 clicks equals an inch at 100 yards. 16 clicks equals an inch at 25 yards.

March 11, 2017, 09:31 AM	#7
243winxb Senior Member Join Date: July 26, 2011 Location: USA Posts: 1,730	Shim the mount first , if possible. Its best. Shim inside the rings as the 2nd choice.

March 11, 2017, 04:33 PM	#9
Blindstitch Senior Member Join Date: April 14, 2013 Location: Milwaukee, Wisconsin Posts: 2,693	I think you need to post up a picture of your rig. What is it exactly. I shoot a Barnett Veloci-Raptor and don't trust any store with setting things up for me. I've seen to many cockeyed adjustments. Remove the scope, remove the rings, remove the base if it comes off. Then place the crossbow in a gunvise, arrangement of pillows or something to keep it steady and reassemble keeping things level and retest. Your POI can also move if you're holding the crossbow wrong. Cocked a bit to one side or the other will throw you off as you move farther away from the target.

March 11, 2017, 06:07 PM	#10
tpcollins Senior Member Join Date: February 18, 2009 Location: SE Michigan Posts: 558	Here's my Scorpyd Ventilator with the Vortex XBR scope. It has a scope level as well to keep it horizontal when shooting. The one problem with Scorpyd is their short crappy scope rails so I'm hostage to extended ring mounts. I tried several brands but the crappy Hawke mounts were what I liked as far as height. The XBR scope is basically the Vortex Viper Series with a different recticle in MOA and 1 MOA per click. With the article in equidistant MOA, it doesn't align with crossbow trajectories very well. But with it on 4x, and keeping the trajectory apex between the 50 & 60 yard chevrons, I can use it to shoot 31-41-50-59-68 yards very well. But I can also turn up the magnification and use the turret for the yardages as well. The end of the turret up is 70 yards, but because the windage is 20% off center, the erector tube is hitting the side of the scope tube when the elevation maxes out and it skews the poi to the right. I think it's the cheapass Hawke rings. I may try to take the rear ring and turn it around 180 degrees to see it it gets closer to the scope's center position. Otherwise I'll spend some money for a better mounting system. __________________ What direction did that last shot at Kennedy come from?

March 11, 2017, 07:05 PM	#11
Blindstitch Senior Member Join Date: April 14, 2013 Location: Milwaukee, Wisconsin Posts: 2,693	You do seem to have a lot going on there. Have you tried asking people over on the Crossbow Nation forum. They have a lot of knowledgeable guys there and some are prostaff to certain crossbow brands. Seems like there has to be an easy way to solve your problem and have the level, top rail and whatever is under your zoom ring on the scope. That has to be the longest crossbow scope i've seen.

March 13, 2017, 08:34 AM	#15
NoSecondBest Senior Member Join Date: December 7, 2009 Location: Western New York Posts: 2,736	I suggest you visit archerytalk.com and go to the crossbow sub-forum. You'll learn a bit about scopes and how they're used on crossbows. From reading your OP and following the responses it sounds to me like you don't understand how to properly use/mount/adjust a scope and you don't understand how they're used on crossbows. No offense intended, but you won't get a good answer here until you yourself have a better understanding. If's difficult for other people to answer your questions if you don't understand their answers. Good luck with this.

March 13, 2017, 12:36 PM	#18
Blindstitch Senior Member Join Date: April 14, 2013 Location: Milwaukee, Wisconsin Posts: 2,693	There should be enough room to shim what you need. Pieces of pop cans make great shims. Shouldn't take much. Were the Crossbow Nation people not willing to help? Someone has to have your same setup there.

March 13, 2017, 03:42 PM	#20
Blindstitch Senior Member Join Date: April 14, 2013 Location: Milwaukee, Wisconsin Posts: 2,693	That XR mount looks like a good solution. Should eliminate any misalignment of two piece mounts.