Shooting 24" to the right

fiftycalforsquirrels

fiftycalforsquirrels

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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.
 
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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.
 
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.
 
tiriaq said:
Two rails bowed - or is it the receiver?
Click to expand...

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.
 
Bore sighting would save some grief. Even before you cinch everything down and then after. Center the reticle first like you do is always a good idea. If you have done that one thing that really helps is to put a vertical line one a wall behind the scope a few feet then from the front line up the bore with the vertical line and then see how far out the reticle windage is. It’s also a good way to tell if your scope is level. A lead sled is great for this process. Also looking through the scope from the front with the bore directly below the scope front objective the reticle should be in the center of the scope if your mounts and rings are perfect. If you have to move your head away from the bore to center the reticle that means your scope is crooked and not parallel to the bore or centred longitudinally.
 
Perhaps I’m off base but I assume that switching to a 30 MOA base from a 20 suggests you intend or are shooting at extreme distances.
If that is so then I’d be concerned that your correction has regulated your zero to a given distance. I’m no long range shooter but if the scope is offset from the bore then an I would assume the bullet path converges as it flys towards the zero and diverges from it afterwards which at great distance is likely a bad thing…I assume, I could be wrong on the whole theory of it but that is what my thinking would be.
If you use the same offset inserts front and rear orientated in the same plane the you are moving the scope over inline with the bore, if you have different inserts you put the scope at an angle to the bore. Normal ranges likely negligible differences but somewhere out there it’s likely measurable.
Why not use the known 20 MOA base and use inserts to get the other 10?
Also, I’d find a known straight edge because scope rails are not meant to be warped and then pulled true (to my knowledge).
To add did you try the original scope on the new rail and try that, perhaps your scope is contributing (?)
 
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