Shooting 24" to the right

[fiftycalforsquirrels]

The rifle in question is a Savage model 12 with an aftermarket barrel that shoots 24" to the right at 100 yards with the windage turret at mechanical zero.

When I first got the rifle, it had a steel 20 moa base on it. I mounted a bushnell 4200 on it with a set of Burris Signature Zee rings with 0/0 inserts. The rifle shot 2 minutes to the right with a mechanical zero on the scope....close enough.

Then I decided to put my Sightron SIII on. In doing so, I changed the scope rail to a 30MOA MDT rail and Burris Signature XTR rings. 0/5 on the insert. Mechanical zero on the scope. Bang.... 24" to the right. Put a 20moa shift to the left insert in there, bang... within 1/2 minute on the windage.

Normal scope mounting procedure for me is to put the rifle in the bags so the stock sits square to the bags and then plumb bob the reticle square.

I did note that the mdt rail is bowed out of the box and rocks on the action. (2 different 30moa MDT rails, exact same bow and rock) but when torqued down the rail is flat.

What gives? Guess process of elimination of swapping the rings front to back(or 180°), changing rail, changing rings, changing scope... blah. Could just leave it with the 20 insert cause it's bang on now...but I lose sleep over stuff like this especially knowing a previous ring rail scope set up within 2 minutes on the windage.

 

[bearhunter]

That's why you buy the "cool" rings, which are expensive and work very well.

Now you want to check if it will still be close to zero further out. If it does, all is well.

I found out the hard way, not all scope bases/rings are created equal.

 

[fiftycalforsquirrels]

Yes... if it goes straight on the windage line at some distance that will be real sweet. You're probably right.... not all created equal... I just cant help but think something is wrong....even though its basically fixed with the inserts.

 

[tiriaq]

...

I did note that the mdt rail is bowed out of the box and rocks on the action. (2 different 30moa MDT rails, exact same bow and rock) but when torqued down the rail is flat.

Two rails bowed - or is it the receiver?

 

[kamlooky]

Weaver two piece bases with the same number.
Lost count on the times I’ve done the dance.
Put one on and level the ker-pow in the vice.
Put t’uther awn and check level.
Not level. WTF?

Nuff tuh drive uno tuh drink.

 

[todbartell]

I have twin Howa 1500 6.5 Creedmoors, both use MDT 20moa picatinny rails

I have one scope I swap between the rifles. At 100 meters it's about 24moa windage between the two rifles, elevation is within a few MOA

 

[bearhunter]

Given the use of CNC machines when manufacturing receivers and barrels, it would be reasonable to assume that with late manufacture firearms, bases, rings, and scopes, a person should be able to swap scopes from one rifle to another without having to change windage or elevation, as long as the loads are equal.

That just isn't the case.

There's a very good reason bases have generous clearance around the screw holes and tapers for the screw heads to pull them to center.

 

[toebako]

I would toss the rails and go with high quality steel. I gave up on rails and got a NEAR Alpha Hunter. Easiest mount and sight in ever. Saved me a pile of money in the long run.

 

[fiftycalforsquirrels]

Two rails bowed - or is it the receiver?

I wondered that... but I think its the rail(s). The steel rail I took off doesnt rock on the action. When I put the steel rail and the MDT rail ontop of each other(top surface to top surface) the MDT is bowed compared to the steel one. When I torque the MDT rail down and then place the steel rail on it top side to top side, the MDT is flat

The 2nd MDT rail wasnt checked on my action. It was a separate Savage model 12. Same rock on the action, same bow compared to the steel rail, and going flat when torqued down.

The steel rail didnt rock on either model 12 action.

Not exactly scientific and could get more precise... but it's close enough for me to determine that the rail isnt neutrally straight and flat.