Burris XTR Signature Rings...Help! Should I have bought a simpler set?

[RussellC]

Good heavens, the more I learn the more I realize how much I didnt learn. Enter my idea for varmint/target gun based on Savage 12 FV in .223 Remington. I wanted a good scope mount without breaking the bank, but wanted something nice enough I wouldnt itch for an upgrade right away.

Bought a Nightforce scope base, and mounted that. I was going to do the full meal deal and go with polish on the receiver, JB weld epoxy underneath to true it, etc. Most of the instructive videos, like on Longrangeonly.com showed mounting one side and noting some visible flex when other side was pressed down. The Nightforce remained flat as a pancake and I was unable to slide even the thinnest piece of paper in the non existent gap, so for now, tightened it down regular style.

Rings arrive and confusion began. Really nice, heavy rings, about 99.95 w/ free ship but the instructions are puzzling me.

https://www.midwayusa.com/product/1...actical-signature-picatinny-style-rings-matte

The mounts instructions explain about the inserts, which seemed like a good idea for protection of the scope. Problems for me start with the fact they are designed to allow for 5, 10, 15, 20, 25, 30, and 40 MOA of cant. I just wanted 0 MOA cant, my scope base is 0 MOA, but that is for a gun that will mostly be shot at 100 yards, occasionally 200 or 300 yards. But I may later use them on a 6.5 or .308 at longer distances, replacing the .223 with simpler rings.

For now, I want to use scope and rings on the .223. The rings have the 0 MOA installed from the factory in one ring, the 5 MOA in the other.


in the case there is +/- 20 MOA (2 sets), +/- 5 MOA, +/- 10 MOA, and Concentric (Zero MOA)

There is chart that makes no sense to me: Any tips to simplify from someone knowledgeable about these ring? Here are the entire instructions: (do I feel dumb tonight!) Do I need to contact Burris and buy another concentric (Zero MOA) inserts?

would the + 5 MOA bottom, -5 MOA top in the rear and 0 MOA in front be as close as it gets? Or should that be -5 MOA bottom rear, +5 MOA top? Oh these are the "High" versions, not extra high.

http://www.burrisoptics.com/sites/d...ucts/manuals/xtrsignatureringsinstruction.pdf

 

[RussellC]

Maybe -5 bottom rear, 0 top rear, and 0 bottom front and +5 top front? (or some such combo) I do understand that one purpose of these rings is to get your point of aim as close as possible without twiddling the scopes elevation and windage, then using them to fine tune. At my distances, especially the 100 yard range, all that isnt necessary.

Confused,

Russellc

 

[climbnjump]

Maybe -5 bottom rear, 0 top rear, and 0 bottom front and +5 top front?

Nope, you need to use them in matched sets with the +/- 5 pair in either front or rear and the concentric pair together in the other.

No need to try to figure out the Burris instructions if you don't want to, just try this instead:

With your rifle on a steady rest (vise is good), put 1/2 of the concentric pair in the bottom mount both front and rear and lay your scope in the rings. Assuming your scope elevation is centered, sight through it at a target marked off in inches and note where the point of aim is on the target - POA1. Now, turn the elevation knob on your scope DOWN 5 MOA, sight on the target again and take note of POA2. Next, replace the concentric insert in the bottom rear mount with whichever of the +/- 5 inserts that moves your POA2 back toward POA1 - keeping in mind that it might not go all the way back to POA1. Place the other +/- 5 insert on top of the scope in the rear ring and the other concentric insert in front ring and torque away.

I think that should work, but I did sample a fine bourbon a bit ago and wrote this between innings of the ball game, so...

 

[RussellC]

Nope, you need to use them in matched sets with the +/- 5 pair in either front or rear and the concentric pair together in the other.

No need to try to figure out the Burris instructions if you don't want to, just try this instead:

With your rifle on a steady rest (vise is good), put 1/2 of the concentric pair in the bottom mount both front and rear and lay your scope in the rings. Assuming your scope elevation is centered, sight through it at a target marked off in inches and note where the point of aim is on the target - POA1. Now, turn the elevation knob on your scope DOWN 5 MOA, sight on the target again and take note of POA2. Next, replace the concentric insert in the bottom rear mount with whichever of the +/- 5 inserts that moves your POA2 back toward POA1 - keeping in mind that it might not go all the way back to POA1. Place the other +/- 5 insert on top of the scope in the rear ring and the other concentric insert in front ring and torque away.

I think that should work, but I did sample a fine bourbon a bit ago and wrote this between innings of the ball game, so...

Thanks, that makes sense. Enjoy the bourbon. I used to have a stunning bunker, rare scotch too.

Had to give it up over a liver condition occasioned from sky high iron levels. Alls good now, but the whiskey had to go. Rather rough on a Kentucky boy, but there are worse things. Plus I am saving a fortune I can spend on this stuff!

Russellc

 

[Varminterror]

What diameter of scope tube? I'm assuming 30mm, but wanna be sure... if they are 1", I have a couple sets of 0's, if you're really wanting to get flat, I'll send you to make your life easier. I thought I had spares in 30mm, but apparently I sent those all out already (or they're in some other drawer where they shouldn't be and I just can't find them).

The instructions aren't really necessary - as a guy who loves to figure out all of the math, it's just not really pertinent in your application. But if you DO want to use the instructions: the markings on the inserts don't mean anything without that chart. If you know your ring spacing center to center, then you can mix and match different insert sets to see how far you're actually adjusting your scope angle. The inserts are marked for 4.75" spaced rings, farther apart and they move the scope less than their markings, closer together, they tilt the scope more. Putting a 0 and a 5 in the rings with a down tilt won't be flat (-5 on bottom in front or +5 on bottom in back), but it will be as close as you can get with that combination.

The instructions seem odd at first - if you have a +5 on top in front and a +10 on bottom in back, that is 15 together. For rings at 4.75", that would equal 15moa of up on our POI. Closer rings will be more than 15moa, farther spread rings won't quite be 15moa, as computed and displayed in the chart. If you had +10 on top in front and +20 on top in back, that is a 10 net, tipping your scope UP from bore. Alternatively, a +10 on top in front and a +20 on bottom in back is a 30 down towards bore, raising POI. So it's just a matter of remembering which direction the inserts are moving their end of the scope. + inserts are thicker, and tilting the front of the scope down raises POI. Vice versa.

No need to mess around with rests. In the matched +/- sets, the + is the thicker, the - is the thinner. So putting the + in top in the front moves your POI up, putting + on bottom in the rear does the same. The opposite doesn't have any practical application with your base, as there is no reason to tilt your scope UP from the bore when you're on a flat base.

A .223rem should have to compensate for ~2-2.5" drop by 100yrds, plus a 1.5" optic height on a bolt gun, you're talking 3.5-4" of correction from optical center. Instead of dialing up 4, your down tilt with the 0 and 5 inserts will mean you dial down 1-ish, depending upon your ring spacing. So you'll end up just a bit closer to optical center by using that down 5 tilt than a pure flat set.

Personally, if my scope had enough adjustment, I'd put a pair of 20's in and have myself at the top of the range. Maybe you won't need the angle today, but maybe someday you will, and you already own all of it, it won't hurt anything to stick them in. But if you're wanting to stay flat, the 5 & 0 will be closer than 0 & 0, but like i said, if they are 1" and you want the 0's, I have a set I'll send you.

 

[Walkalong]

Whew, prices are sure up over the last few years. Not $75 anymore. Worth every penny though.

https://www.midwayusa.com/product/845031/tps-tsr-picatinny-style-rings-matte

I have a 20 MOA base on my .308 and so far have only shot 300 yards with it. It is not a problem at 300, and if I get the chance to shoot longer, I'm ready.

That said, if you are not going to be shooting over 300 yards, you don't need any extra MOA built in. Just use 0 & 0 and you'll be fine.

 

[climbnjump]

Just use 0 & 0 and you'll be fine.

Yepper, that would work - if there were 2 0 MOA insert sets provided with the rings. But there is only one set.

The OP could request a second 0 MOA set from Burris, or he could take up Varminterror on his offer to send his spare set of 0 MOA inserts.

Or, he could just go ahead and use the 0 and 5 MOA inserts that he has (which it sounds like he has done, based on a post in another thread) and he'll be just fine there also.

 

[RussellC]

What diameter of scope tube? I'm assuming 30mm, but wanna be sure... if they are 1", I have a couple sets of 0's, if you're really wanting to get flat, I'll send you to make your life easier. I thought I had spares in 30mm, but apparently I sent those all out already (or they're in some other drawer where they shouldn't be and I just can't find them).

The instructions aren't really necessary - as a guy who loves to figure out all of the math, it's just not really pertinent in your application. But if you DO want to use the instructions: the markings on the inserts don't mean anything without that chart. If you know your ring spacing center to center, then you can mix and match different insert sets to see how far you're actually adjusting your scope angle. The inserts are marked for 4.75" spaced rings, farther apart and they move the scope less than their markings, closer together, they tilt the scope more. Putting a 0 and a 5 in the rings with a down tilt won't be flat (-5 on bottom in front or +5 on bottom in back), but it will be as close as you can get with that combination.

The instructions seem odd at first - if you have a +5 on top in front and a +10 on bottom in back, that is 15 together. For rings at 4.75", that would equal 15moa of up on our POI. Closer rings will be more than 15moa, farther spread rings won't quite be 15moa, as computed and displayed in the chart. If you had +10 on top in front and +20 on top in back, that is a 10 net, tipping your scope UP from bore. Alternatively, a +10 on top in front and a +20 on bottom in back is a 30 down towards bore, raising POI. So it's just a matter of remembering which direction the inserts are moving their end of the scope. + inserts are thicker, and tilting the front of the scope down raises POI. Vice versa.

No need to mess around with rests. In the matched +/- sets, the + is the thicker, the - is the thinner. So putting the + in top in the front moves your POI up, putting + on bottom in the rear does the same. The opposite doesn't have any practical application with your base, as there is no reason to tilt your scope UP from the bore when you're on a flat base.

A .223rem should have to compensate for ~2-2.5" drop by 100yrds, plus a 1.5" optic height on a bolt gun, you're talking 3.5-4" of correction from optical center. Instead of dialing up 4, your down tilt with the 0 and 5 inserts will mean you dial down 1-ish, depending upon your ring spacing. So you'll end up just a bit closer to optical center by using that down 5 tilt than a pure flat set.

Personally, if my scope had enough adjustment, I'd put a pair of 20's in and have myself at the top of the range. Maybe you won't need the angle today, but maybe someday you will, and you already own all of it, it won't hurt anything to stick them in. But if you're wanting to stay flat, the 5 & 0 will be closer than 0 & 0, but like i said, if they are 1" and you want the 0's, I have a set I'll send you.

Its a 30mm set, but thanks for the offer. Varminterror, when you talk about zeroing for 3.5 to 4 inches, you say 0 and 5, you mean 5 in back, zero in front, right?

Russellc

 

[Varminterror]

If I find a set of 30's, I'll let you know. I really thought I had a couple sets left, but they're not where they're supposed to be if I do.

As I outlined in my last post - a 223rem bolt rifle should have somewhere on the order of 1.5" between the bore and centerline of the scope, then if the barrel were perfectly level when fired, the bullet would drop another 2-2.5" - so 3.5-4" of drop to account for to zero at 100yrds. With a flat base and "0 & 0" inserts, that'd be 4moa up. If you have "0 & 5" inserts installed, AND have 4.75" ring spacing, you'll have 5MOA up built in, so you'll actually have to dial down 1MOA to get to the same zero. So you're actually closer to optical center by using the 0 & 5 than you would be with 0 & 0. 1MOA off center instead of 4.

It doesn't matter whether you put the offset inserts in the front or the back. A 5 & 0 with the -5 on bottom in the front is the same as a 0 & 5 with the -5 on TOP in the back. The inserts are nothing more than eccentric circular shims - so putting the +5 on bottom in the back raises the tail of the scope, tipping the scope axis down in front, which is the same as putting the +5 on top in the front (-5 on bottom), which drops the front of the scope, again, tipping the scope axis down in front.

So flip a coin . Putting 5 in front and 0 in the back is the same angular offset as putting 0 in front and 5 in the back, the only difference is whether the + is on top, or - is so.

 

[RussellC]

Gotcha. Would one way give a little extra clearance for a 50mm objective, or does it work out to the same thing? Seems like it would be the same thing...

Russellc

 

[Varminterror]

Yes, but no. Technically, even though the scope would be at the same angle whether you run 0 & 5 or 5 & 0, dropping the front by putting the -5 in the bottom front DOES lower the scope overall compared to raising the back by putting the +5 in the bottom back. So yes, putting the -5 in the front bottom does lower the scope compared to putting the -5 in the top in the back...

BUT...

If you're running ~1/16" clearance, it's a distinction without a difference. The -5 is about 4thou thinner than the 0, so you're talking about dropping the scope 4thou... Not enough to make any appreciable difference.

 

[RussellC]

Thanks for that, it did seem like 6 of one, half dozen of the other.

Russellc

 

[RussellC]

Ok, scope is ordered and on the way. The SWFA 12x42. I will wait on the Sightron until back in stock and closer to time 6.5 CM is in hand. Then if necessary, get the shorter Signature XTR rings.

Russellc