effect of adding a 20 Moa rail - 3 questions

[jippy1]

I have a 308 rem700, flat Picatinny rail, and a Horus scope with a Horus reticle.
if I were to swap out rails, for a 20 Moa rail, . . .
does that effect the dope? or just where zero is, in regards to the elevation turret's total travel??

my thought is that it simply give me use of "wasted" come-up travel from the turret, since roughly half of its travel is in the scope's "northern hemisphere", and can't be dialed down, to raise poi at distance

and, as a related question, . . .
I don't see a place in strelock pro, or the Hornaday ballistic app to input 20 Moa, or 40, etc.

so, if I were to add a 20 Moa rail, is my dope unchanged?
and the only thing changed is where I point the scope, (and hence the gun), to do what I want it to do, at a given range


lastly, I am considering getting a Sako s-20, which has a built in rail, but kind-of in 2 pieces

I want +20 Moa for this rife, how do I accomplish that?
add a 20moa Picatinny rail on top of the built in rail?
do they make 20 Moa rings?
get a one piece spur mount with 20 Moa and secure THAT to the built in rail?

 

[Newbie2020]

Your dope does not change. Dope is based on the bullet and cartridge and the load; the rail simply changes the angle that the scope is relative to the axis of the bore of the barrel.

 

[Newbie2020]

Burris has interchangeable shims that go inside the rings to adjust the scope angle up or down.

 

[Steel head]

Dope won’t change
You will have to re zero
You will have to adjust your stock to accommodate the new scope position.

 

[DocRDS]

You've pretty much got the understanding of the rail. The rail moves your Zero. Since your DOPE is all relative adjustments to your zero, your dope doesn't change. That is also why you won't see any adjustments for rails in ballistic apps. (Think of the zero as a point of reference. At this mark my gun hits the bullseye @ 100 yards. Dope is always relative to zero. From Zero I click up 2.2 mils.)

So when you zero with the rail--you re-find that initial reference point, and everything lines up once again.

As you describe, the rail moves the zero of the rifle so most of your scope travel is to move POI up since bullets only fall in one direction...

There are rings and mounts for the Sako that can include the 20MOA elevation. It bit a little bit harder than normal to find, but doable.


rings with inserts:

XTR Signature Rings™ | Burris Optics

www.burrisoptics.com

The Sako 20 is still new, so people may be coming out with new hardware for it.

 

[Newbie2020]

I have the Burris rings. I have a 20 moa rail so I set the inserts for zero additional elevation. However, when I shot a mile I ran out of dial elevation and needed to hold an additional 4 mils. So I’m going to change scope ring inserts to add another 20 moa (5.6 mils) in addition to the 20 moa from the rail.

 

[jippy1]

I have the Burris rings. I have a 20 moa rail so I set the inserts for zero additional elevation. However, when I shot a mile I ran out of dial elevation and needed to hold an additional 4 mils. So I’m going to change scope ring inserts to add another 20 moa (5.6 mils) in addition to the 20 moa from the rail.

what scope/caliber

wanting to mainly do prs, but my range has a mile, which I'd like to do, just for bragging rights

 

[Newbie2020]

I was shooting 6cm using a Burris XTR II 4-20x at 4,300 feet. The scope theoretically has 26 mils of elevation, but w zero stop set and 20 moa rail I only had 15.5 mils available.

 

[jippy1]

I emailed sphur yesterday to see which one to get,
they said NONE of their unimounts would work on the s-20, because of its two part rail design

how difficult are the 20 MOA Burris rings/inserts to install, and get "right"
I did a very good job of installing my Horus falcon, and flat pic rail on my 308
just wondering if I can do this myself

o.k., I can, wondering about the should . . .
very interesting, just watched one video, he had this image of the instructions :

I see how there's a thinner and thicker insert.
the instruction image indicates they they should be offset from horizontal by 45 degrees - ie the ring's equatorial line is NOT parallel to the INSERT's equator.

seems like that is going to introduce some left/right can't, as well, . . . doesn't it?

well, now that I watch a 2nd video, it seems they do NOT have to go in at an angle, and CAN go in with equators aligned parallel to one another.
it seems that the example above is if you are trying to move your p.o.i 2" down, and 2" left.

DO I HAVE IT RIGHT, NOW? FINALLY, after three updates

 

[Newbie2020]

Believe me it’s stupid simple and they work great: mile took me to a mile and another buddy did the same. They work and they’re easy—-I’m no Smith.

 

[Davo308]

I emailed sphur yesterday to see which one to get,
they said NONE of their unimounts would work on the s-20, because of its two part rail design

how difficult are the 20 MOA Burris rings/inserts to install, and get "right"
I did a very good job of installing my Horus falcon, and flat pic rail on my 308
just wondering if I can do this myself

o.k., I can, wondering about the should . . .
very interesting, just watched one video, he had this image of the instructions :View attachment 7481937
I see how there's a thinner and thicker insert.
the instruction image indicates they they should be offset from horizontal by 45 degrees - ie the ring's equatorial line is NOT parallel to the INSERT's equator.

seems like that is going to introduce some left/right can't, as well, . . . doesn't it?

well, now that I watch a 2nd video, it seems they do NOT have to go in at an angle, and CAN go in with equators aligned parallel to one another.
it seems that the example above is if you are trying to move your p.o.i 2" down, and 2" left.

DO I HAVE IT RIGHT, NOW? FINALLY, after three updates

They can be aligned in any position, its at a 45 angle in that pic merely for an example. I plan to pick up a pair to add elevation to a rifle I cant 15 degrees to the left.

BTW, the amount of elevation they add is dependent on the ring spacing.

Tactical Tech: New XTR Signature Rings from Burris « Daily Bulletin

For years we have touted the advantages of Burris Signature rings, with polymer Pos-Align Inserts. Now this system is available in a beefier, heavy-duty ring system for tactical rifles. The new Burris XTR Signature Rings offer six (6) clamping bolts per ring plus strong, dual steel base-clamps...

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Hawke also makes rings that can add elevation (but not cant)...

Adjustable 30mm 2 Piece 9-11mm High

Precision engineered from high grade aluminium with rounded edges prevent scope damage. Adjustable Elevation - Compensation Of +/- 30 MOA. High - To Accommodate Larger Objective Scopes. Double Torx Screws To Hold Your Scope Firmly In Place. Fitted With A Recoil Stop Pin. Reversible Dove Tail...

us.hawkeoptics.com

 

[jippy1]

Hawke also makes rings that can add elevation (but not cant)...

Adjustable 30mm 2 Piece 9-11mm High

Precision engineered from high grade aluminium with rounded edges prevent scope damage. Adjustable Elevation - Compensation Of +/- 30 MOA. High - To Accommodate Larger Objective Scopes. Double Torx Screws To Hold Your Scope Firmly In Place. Fitted With A Recoil Stop Pin. Reversible Dove Tail...

us.hawkeoptics.com

so isn't the elevation (adding Moa for distance) just "windage neutral" cant,

whereas if the "equators" aren't aligned, then it is adding +/- elevation can't AS WELL AS +/- windage cant?
do I have that right

 

[Davo308]

so isn't the elevation (adding Moa for distance) just "windage neutral" cant,

whereas if the "equators" aren't aligned, then it is adding +/- elevation can't AS WELL AS +/- windage cant?
do I have that right

Yes. Unless you decide to use them to optically center the scope instead of to add elevation.

The rings come with neutral spacers, you have to buy separately (on most) if you want to adjust elevation with the scope.

If you use the offset shims, you can use them to optically center a scope (I do this on airguns), or to add elevation. That is what the guy in the video is doing.

Once installed, like a base you never have to think about it again unless you are calculating drop for long distance.

 

[High H2o]

Dope is the same. Your scope’s zero will change since your scope is now pointed “down” compared to the previous zero.

the easiest way to add MOA to a fixed rail will be with a one piece mount (spuhr, for example) that has built in angle. It’s possible, I think Burris sells something, to shim a set of rings to include some angle. I’ve never used that setup though.

Did that to a Sako, gotta watch the ejection...