Rifle Scopes Scope Windage Zero Problem

[Biscuits]

More a scope mounting problem but anyway.
Remington 700 .308 with a Vortex HS-T 4-16x44 scope.
Having asked around about this problem, it is possible that the holes drilled into the receiver to mount the picatinny rail may not be dead centre, so the rail is not quite true to the barrel. Although maybe it is something else, so appreciate any ideas.

The problem is that my windage bullet impact zero is 3.5 mrad to the left of the optical center of my scope. 3.5 mil is a lot and it used to be even worse. I took the scope off a few months back and remounted it with new rings which were torqued right. But before that with the old rings, the zero wind bullet impact zero was 8 mrad left of the optical center. The effect of this is that you have more available windage adjustment to in one direction than the other. At the time, i had 4 mrad of available windage adjustment to the left and about 19 mrad windage adjustment to the right. It was possible to run out of left hand windage adjustment for long range shooting in full value crosswinds.

I have just bought a Schmidt & Bender PMII 3-20x50 scope. It has a lot of elevation adjustment but only +/- 6 mrad of windage adjustment. This means when I mount it, I need to get the windage zero aligned to the optical zero of the scope, so I get the full 6 mrad in each direction.

Can anyone diagnose:
- What is the problem with the present set up which is pushing windage zero away from optical center?
- How can I fix it when I mount the new scope?

 

[JMGlasgow]

Burris XTR Signature rings with inserts or have the scope mount holes recentered and enlarged to 8-40 screws, or try a different base.

 

[m1match]

I think your S&B actually has much more windage than 6 mils each direction from optical center but the turrets are stopped so they won't give you more than 6 mils each direction. Use the zero stop to make sure you have enough travel to get to your zero then use the zero stop to set the turret to 0/

 

[Biscuits]

I think your S&B actually has much more windage than 6 mils each direction from optical center but the turrets are stopped so they won't give you more than 6 mils each direction. Use the zero stop to make sure you have enough travel to get to your zero then use the zero stop to set the turret to 0/

I will have to investigate. 6 mil windage either direction is unusually low for a 34mm tube scope. I should have also mentioned, it is the 3-20x50 PM II Ultra Short, https://www.schmidtundbender.de/en/products/police-military-forces/3-20x50-pm-ii-ultra-short.html

 

[308pirate]

Either use the rings mentioned elsewhere in this thread to offset your crap receiver or send the rifle to a reputable gunsmith to have the scope base mounting holes redrilled on center, if that's even possible.

The existing holes may be off center just enough to not clean up completely when the new holes are drilled unless the new holes are way oversized. Unless you have the gauging and fixtures to indicate everything in, a gunsmith will have to measure everything.

 

[supercorndogs]

What rings were you using that had you 8 MIL out of center? What ring did you change to that corrected that by 5 MIL. What base?

Its possible the base holes are not straight. There are places like LRI, that will open them and cut them straight. It is also possible that your barrel or the threads the action are crooked. Where as a ring change made such big correction, i wonder about the rest of you components and their compatibility or quality. Some pictures may help.

 

[Biscuits]

What rings were you using that had you 8 MIL out of center? What ring did you change to that corrected that by 5 MIL. What base?

Its possible the base holes are not straight. There are places like LRI, that will open them and cut them straight. It is also possible that your barrel or the threads the action are crooked. Where as a ring change made such big correction, i wonder about the rest of you components and their compatibility or quality. Some pictures may help.

Here are a couple of pics.

TierOne (i.e. expensive) rings, though now I look at the pic the gap between top and bottom halves of the rings isn't uniform across both sides. The setup shown below in pictures has the windage zero 3.5 mrad left of optical centre. The previous set up was with same scope but mid-range quick detach rings, can't remember which brand. That was 8 mrad off optical centre. I do not think anything was wrong with the previous rings. I've since put them on a Tikka T1x rimfire and the windage zero is dead on optical zero. Did not need to adjust windage even one single click off optical zero.

When I mounted the scope with these rings, I was aware of the windage problem so tried to press on one side of the rings while tightening them on the rail to correct it. Not sure if that made any difference or not.