How to tell you have a 20 MOA base?

[m12lrs]

I think you hit it Doc. With the loooooong sun shade on the scope, I can't see any difference in spacing between the barrel and scope, but then the barrel is tapered in exactly the direction that would make it look parallel to the scope IF the scope were canted down slightly.

And as I was setting the scope back in the rings yesterday before going to the range, I noticed that with the top halves of the rings off, when I press on the scope body over the rear ring, the front of the scope rises off the front ring slightly. So the rings are not exactly in line, another sign that I need to get a one piece rail with a 20 moa lift if I'm going to pursue ringing steel at long distances.

Quite a learning process!

now that is a really bad situation. Not at all good for a scope. I would not even install a scope in rings like that. If it is not too bad lapping your rings could fix it. Otherwise you need to go in a different direction.

[m12lrs]

I think you hit it Doc. With the loooooong sun shade on the scope, I can't see any difference in spacing between the barrel and scope, but then the barrel is tapered in exactly the direction that would make it look parallel to the scope IF the scope were canted down slightly.

And as I was setting the scope back in the rings yesterday before going to the range, I noticed that with the top halves of the rings off, when I press on the scope body over the rear ring, the front of the scope rises off the front ring slightly. So the rings are not exactly in line, another sign that I need to get a one piece rail with a 20 moa lift if I'm going to pursue ringing steel at long distances.

Quite a learning process!


dude it is quite simple. If you have considerably more up elevation adjustment then you do down adjustment from your 100 yrd zero you have canted scope bases.

[rovert]

dude it is quite simple. If you have considerably more up elevation adjustment then you do down adjustment from your 100 yrd zero you have canted scope bases.

It's not quite that simple. In a perfect world it would be. If they are two piece bases I'm pretty certain they are not meant to be 20 MOA bases. I've never seen such a thing. It would be possible but I don't know that anyone offers them. The bases would definitely long action/short action specific and the front and back bases would have to be oriented properly.

I doubt that is the case here. I see three possibilities. One is the action is quite far out of spec. Two is the bases are out of spec or are not the correct bases. Three is the rings are out of spec. As things are described I would lean towards the bases being incorrect. Something is misaligned pretty badly if the scope lifts off the front ring when placed squarely in the rear. Take the rings off and put a straight edge on the rear base. If it floats over the front it is not the rings. Take the bases off and put the straight edge on the action. If, when held tight to the rear screw tappings, it floats at the front screw tappings it is an action problem. If the action is straight it is a base problem.

The action test assumes a round receiver. If this is a rear flat receiver I almost bet that the bases were not matched properly for the application. If you want to keep the 20 MOA two piece system that you have stumbled on to I would suggest Burris Signature rings. They should allow the scope to be secured without applying unwanted torque to the tube. You may be able to lap the rings to accomplish the same but it sounds like a lot.

Best solution: get a real 20 MOA one piece base. (If the action is ok)

[m12lrs]

It's not quite that simple. In a perfect world it would be. If they are two piece bases I'm pretty certain they are not meant to be 20 MOA bases. I've never seen such a thing. It would be possible but I don't know that anyone offers them. The bases would definitely long action/short action specific and the front and back bases would have to be oriented properly.

I doubt that is the case here. I see three possibilities. One is the action is quite far out of spec. Two is the bases are out of spec or are not the correct bases. Three is the rings are out of spec. As things are described I would lean towards the bases being incorrect. Something is misaligned pretty badly if the scope lifts off the front ring when placed squarely in the rear. Take the rings off and put a straight edge on the rear base. If it floats over the front it is not the rings. Take the bases off and put the straight edge on the action. If, when held tight to the rear screw tappings, it floats at the front screw tappings it is an action problem. If the action is straight it is a base problem.

The action test assumes a round receiver. If this is a rear flat receiver I almost bet that the bases were not matched properly for the application. If you want to keep the 20 MOA two piece system that you have stumbled on to I would suggest Burris Signature rings. They should allow the scope to be secured without applying unwanted torque to the tube. You may be able to lap the rings to accomplish the same but it sounds like a lot.

Best solution: get a real 20 MOA one piece base. (If the action is ok)

you missed my post above. I would not even install my scope in rings like that. You could damage the scope.

the post you referenced was just to tell if you had a canted installation.

[yobuck]

Wow. I never thought about that. Not to mention angle of the sun and it's reflective properties. You know that black is the presence of all colors lol.

I actually didnt know that, but it might help explain a few other things i dont understand either.

As for the 2 pc Leupold base, theres not a thing wrong with using them.
If your having issues with elevation, try removing just the rear section and
installing a few thickness of your favorite beverage can as shims. See if that helps
with the zero issue. At least you will have done something that wont hurt or cost anything.
There was a time in the not very long ago past that tapered piccitiny bases werent available.
And the only way to deal with getting max elevation was to have the base milled or install shims.
I might still have some shims under a Redfield base on one of my guns.

[barrel-nut]

It's not quite that simple. In a perfect world it would be. If they are two piece bases I'm pretty certain they are not meant to be 20 MOA bases. I've never seen such a thing. It would be possible but I don't know that anyone offers them. The bases would definitely long action/short action specific and the front and back bases would have to be oriented properly.

I doubt that is the case here. I see three possibilities. One is the action is quite far out of spec. Two is the bases are out of spec or are not the correct bases. Three is the rings are out of spec. As things are described I would lean towards the bases being incorrect. Something is misaligned pretty badly if the scope lifts off the front ring when placed squarely in the rear. Take the rings off and put a straight edge on the rear base. If it floats over the front it is not the rings. Take the bases off and put the straight edge on the action. If, when held tight to the rear screw tappings, it floats at the front screw tappings it is an action problem. If the action is straight it is a base problem.

The action test assumes a round receiver. If this is a rear flat receiver I almost bet that the bases were not matched properly for the application. If you want to keep the 20 MOA two piece system that you have stumbled on to I would suggest Burris Signature rings. They should allow the scope to be secured without applying unwanted torque to the tube. You may be able to lap the rings to accomplish the same but it sounds like a lot.

Best solution: get a real 20 MOA one piece base. (If the action is ok)

Winner winner chicken dinner. Best answer by far.
My guess would be that the action is out of spec. I've run into that before.
To continue using the same bases, shim under the low one as yobuck suggested. Except use shims made for the job: http://www.midwayusa.com/product/1548585609/burris-scope-base-shims-1240x735-package-of-10
Or switch to a one-piece rail. Which should be shimmed as well, to get proper contact, or bedded, or neither if you're in a hurry.

[Texas10]

Thanks for all the responses, guys. Really learned a lot about scopes, bases , rings and alignment, and appreciate you sharing your experiences and wisdom.

The scope on my Savage shoots great, despite the irregularities. Got plenty of up adjustment for 750 yard shooting, and may even go for 1000 some day, but apparently it is all an accident. Nevertheless, it works. I will continue to plan on getting a 20 moa one piece base and some better rings soon, if for no other reason than to have a reliable set up that i can move to another gun if necessary.

Thanks again.

[bajeep93]

It's not quite that simple. In a perfect world it would be. If they are two piece bases I'm pretty certain they are not meant to be 20 MOA bases. I've never seen such a thing. It would be possible but I don't know that anyone offers them. The bases would definitely long action/short action specific and the front and back bases would have to be oriented properly.

I doubt that is the case here. I see three possibilities. One is the action is quite far out of spec. Two is the bases are out of spec or are not the correct bases. Three is the rings are out of spec. As things are described I would lean towards the bases being incorrect. Something is misaligned pretty badly if the scope lifts off the front ring when placed squarely in the rear. Take the rings off and put a straight edge on the rear base. If it floats over the front it is not the rings. Take the bases off and put the straight edge on the action. If, when held tight to the rear screw tappings, it floats at the front screw tappings it is an action problem. If the action is straight it is a base problem.

The action test assumes a round receiver. If this is a rear flat receiver I almost bet that the bases were not matched properly for the application. If you want to keep the 20 MOA two piece system that you have stumbled on to I would suggest Burris Signature rings. They should allow the scope to be secured without applying unwanted torque to the tube. You may be able to lap the rings to accomplish the same but it sounds like a lot.

Best solution: get a real 20 MOA one piece base. (If the action is ok)

Now you have seen it
https://www.midwayusa.com/product/591376/nightforce-2-piece-20-moa-picatinny-style-scope-base-savage-10-through-16-110-through-116-round-rear-axis-matte

[FW Conch]

^ that product has been discontinued by Midway. ^

The same 20 MOA 2 piece bases cannot work on both a long and short action. That Geometry does not work. Maybe Midway should have listed an option for both the long and short actions. Or maybe they didn't sell because of the $86 price tag, which is ridiculous, even for Night Force.

But I think the mix up on this product listing is with Midway, not Night Force ?

"T 10" you now know all you could ever know about a problem you don't have! :-) As you said, your rifle shoots well. But if you still want to perfect away the issues you may have, you've answered those questions also. Go with a one piece base, or the Burris Zee rings. :-) The Brotherhood always comes through! :-)

[pitsnipe]

If she is FUBAR'd I'd say she's FUBAR'd in the right direction ;)


+1 on that



Snipe

[barrel-nut]

Thanks for all the responses, guys. Really learned a lot about scopes, bases , rings and alignment, and appreciate you sharing your experiences and wisdom.

The scope on my Savage shoots great, despite the irregularities. Got plenty of up adjustment for 750 yard shooting, and may even go for 1000 some day, but apparently it is all an accident. Nevertheless, it works. I will continue to plan on getting a 20 moa one piece base and some better rings soon, if for no other reason than to have a reliable set up that i can move to another gun if necessary.

Thanks again.

Never meant to imply that it's an "accident". It simply is what it is. Sounds like the only problem that you have with your setup, is that your bases are not on the same plane with each other, which is hard on your scope tube when tightened down. I would suggest trying to correct that situation before installing any scope that you value very highly, because it may well cause damage. There are several routes to do this, many have already been mentioned. Just be aware that fixing this problem may actually cause you to have less elevation available than you do now. Up to you to decide if you want to leave it as-is or try to level out your rings.
The Burris rings with inserts mentioned above are another good option if you decide to mess with it.