Thoughts on shimming windage

[mrb1982]

I am working on aligning my Talley One Piece mounts or my rifle. I have read to fix windage alignment on these that I would probably have to shim them. Seems that adding shims to the rings is going to change the ring to scope contact and possibly harm the scope? If you do endorse shimming, what kind of material do you recommend? I have read anything from tape to beer cans?????

Also, I have heard of people just compensating for the alignment errors in their drop charts. Kinda cheating the system a little but curious how they do that. I assume shooting on an absolutely still day to figure out how much it is off and then setting the offset in the shooting program is how that works????

Thanks ahead of time for your advice.

 

[MTBULLET]

BURRIS signature posi-line insert rings

 

[mrb1982]

Yeah, I have read about a million things about those. Just not sure how I feel about the weaver style mounts. I really like these mounts I have, and I am about ready to do a little testing on them and checking the mount on it. When I mounted it, I did so without as much knowledge about it as I have right now, so I am trying to gain a little more knowledge about it before I dive into it.

Does anybody out there shim without the burris signature rings?

Does anybody out there ever just build any offset into their charts????? Kinda wondering what all the options are, along with the Burris rings, as already noted.

Thanks for the reply.

 

[Canadian Bushman]

BURRIS signature posi-line insert rings

+1

If i was worried about perfect alignment this is the route id take.

 

[mrb1982]

You guys are starting to sway me.

Tell me about the signature's. I have read a fair amount about that. I want to know about durability. I want to know how well they hold their zero. I want something that once it is locked down, it is solid, set in stone. That is my one thing I like about the Talley one piece lightweights. I want some good, rigid stuff. Give me some rock hard, solid review to give me the confidence I need in them!!!! lol I shoot a 7RM Sendero with a brake so it isn't anything too wild, but I just want to feel confident about them when I put them on.

Also, would I want the "Universal" or the "Zee" rings? I want whichever is the sturdiest setup.

I assume that instead of adjusting windages, I have to change inserts, would that be correct?

 

[Canadian Bushman]

+1

If i was worried about perfect alignment this is the route id take.

I run NF rings and bases and never had an issue.
I square up my reticle and level and run a box test and off i go.
So far my windage corresponds to spin drift and wind readings out past 1200. If i have windage problems i have never known about it.

 

[mrb1982]

When I got it all together this summer, I sighted at 200. Then I went to 400 and it was shooting a little bit right. So I made a few adjustments, life was great. Then I went out to 685 a few weeks later. It was shooting left, so I tuned a few things out and got it on a 700. I am just concerned that some of this is due to misalignment. I have a anti cant level that I am pretty specific about. So I ordered a good tool to check alignment. My bases actually line up pretty good. They may be just ever so slightly misaligned at the bases, not even sure if it is enough that I can really tell. I just need to do some good thorough testing to make sure for piece of mind on my own, to know if it is something with the way I was shooting, or something of misalignment.

In theory, if I did the shooting test with the plum line and turning the turrets to different elevations, I should be able to essentially rotate the scope to offset any misalignment that there may be, in theory, correct? I should be able to rotate it so that my points of impact are in the same line, even if there was misalignment, correct?

 

[Canadian Bushman]

Usually when scopes are not aligned the deflection is always linear.
I.E. always left and low, or always right.

If youre using two piece bases i would suggest a one piece rail.

You could maybe correct for inproper alignment by canting the scope, but i would attack this problem in a much more proper manner.

 

[mrb1982]

I did a little testing when I was home on my lunch break today. Got the windage set to the middle. Lined up a spot in the bore. Looked through the scope. It was actually pretty close. Most of the error could be attributed to error lining up the bore depending on how you line it up. Last step is to get this ring true alignment tool that I ordered and see if possibly my alignment from bore to scope to anti cant level is accurate. For some sneaky reason I have a feeling that might be part of the problem. I can't wait for it to get here to find out.

 

[Canadian Bushman]

I did a little testing when I was home on my lunch break today. Got the windage set to the middle. Lined up a spot in the bore. Looked through the scope. It was actually pretty close. Most of the error could be attributed to error lining up the bore depending on how you line it up. Last step is to get this ring true alignment tool that I ordered and see if possibly my alignment from bore to scope to anti cant level is accurate. For some sneaky reason I have a feeling that might be part of the problem. I can't wait for it to get here to find out.

If your scope is not plum to the center of your rifles bore, or your level true to the verticle axis of your turret, you will know when shots began to drift left or right in proportion to the elevation dialed.

To check this get the tallest target feasable and draw a long verticle line. Use a plum bob to level this target. Then shoot 3 shot groups increasing elevation. I like to do 5 or 10 moa at a time and over the elevation you use most often. I try for 20-30 moa.

This lets me check the level of my optic and its actual adjustment value.

If they dont follow the line you know whats going on.

The same test can evaluate windage. Aka a box test.

 

[mrb1982]

When you do this elevation test, at what point do you consider it "acceptable" so to speak?

It seems it would be pretty hard to get rotate the scope the perfect amount to get it perfectly verticle. Is it as hard as it sounds?

My plan is to check the alignment of how the scope is mounted currently with this alignment tool. If I have things aligned properly, then I am going to do a shooting test on it. If it isn't aligned properly, then I am going to square things up with the tool, then give it a try.

When I mounted the scope, I was a rookie at it. I put a level on the rings, locked the gun down when level, then put a level on the scope turret, put the ring caps on. then with it still locked down, put the anti cant on. I think that this tool I have bought will be a little more accurate though. I am not confident with the way the old level I was using had to balance on the top of the turret. I am hoping this works better. This tool should also allow me to align the scope to the bore more accurately. Then if I need to cant the scope ever so slightly, it shouldn't be a problem. As long as my levels coincide, and my elevation travels vertically, life should be good I hope.

The gun is a good shooting gun. Best group at 685yds was 3 1/8" so I was fairly happy with that. And I might just be making a bigger stink about this than needs to be. But I want to go back and check on this stuff a little to make sure it will track properly.

We shot some antelope at 581 and 587yds this fall, but if I want to try to stretch it into the upper hundreds for yardage, I want to try to make sure that it is working properly. Because depending on how much cant it is, can make a pretty drastic difference at 1000

 

[Canadian Bushman]

When you do this elevation test, at what point do you consider it "acceptable" so to speak?

It seems it would be pretty hard to get rotate the scope the perfect amount to get it perfectly verticle. Is it as hard as it sounds?

My plan is to check the alignment of how the scope is mounted currently with this alignment tool. If I have things aligned properly, then I am going to do a shooting test on it. If it isn't aligned properly, then I am going to square things up with the tool, then give it a try.

When I mounted the scope, I was a rookie at it. I put a level on the rings, locked the gun down when level, then put a level on the scope turret, put the ring caps on. then with it still locked down, put the anti cant on. I think that this tool I have bought will be a little more accurate though. I am not confident with the way the old level I was using had to balance on the top of the turret. I am hoping this works better. This tool should also allow me to align the scope to the bore more accurately. Then if I need to cant the scope ever so slightly, it shouldn't be a problem. As long as my levels coincide, and my elevation travels vertically, life should be good I hope.

The gun is a good shooting gun. Best group at 685yds was 3 1/8" so I was fairly happy with that. And I might just be making a bigger stink about this than needs to be. But I want to go back and check on this stuff a little to make sure it will track properly.

We shot some antelope at 581 and 587yds this fall, but if I want to try to stretch it into the upper hundreds for yardage, I want to try to make sure that it is working properly. Because depending on how much cant it is, can make a pretty drastic difference at 1000

Less error than the accuracy of the rifle at your furthest range.

Its extremely difficult to clock a scope to comp for a windage deviation without knowing the erector position, length, or angle. Which is why i advised against that methodology for compensating for your crooked bases.

Your gonna check the rifle with the tool, and once it checks out then youll shoot it, and if it shoots poorly, youre gonna fix it with the same tool?

I never level off the rings.
I set two levels on my base (forward and aft), one on the elevation turret, and i align the reticle with a plum bob 100 yards away.
Do this at your lowest and highest elevation setting and youll be very close.

This tool also helps.
http://www.longrangehunting.com/forums/f18/best-method-system-leveling-scope-64348/

 

[mrb1982]

I like your idea of aligning at your lowest and highest setting. Seems that would reach somewhat the same conclusion as the shooting method.

So in the end, the level on your turrets is just to get you close so that when you do your test with your elevation at it's highest and lowest, it is easy to adjust?

 

[Canadian Bushman]

I like your idea of aligning at your lowest and highest setting. Seems that would reach somewhat the same conclusion as the shooting method.

So in the end, the level on your turrets is just to get you close so that when you do your test with your elevation at it's highest and lowest, it is easy to adjust?

Yup and it provides a ref point in case the scope rolls when tightening the rings.