Typical windage adjustments needed when zeroing rifle?

[rmiked]

I realize the windage adjustments needed when zeroing a rifle are dependent on the manufacturing tolerances of the rifle, scope base, and scope. Assuming the scope is optically centered from the factory, it’s basically how well the bore centerline is matched up with the scope mounting system. I just sighted in my Seekins PH2 in 7 PRC. Shoots well. Once sighted I had a 3 shot group at 0.35” at 100 yards. I didn’t bore sight the scope (no prior scope adjustments) but it was 8.5” right at 100 yards. That’s about 8.5 MOA. Once zeroed I don’t guess it matters. I have a Nightforce scope, Seekins 20MOA base with 5, #8 screws attaching the base to the action. I used some Burris XTR tactical rings I had from a previous rifle. Last year I sighted in a Seekins SP10, Nightforce scope, Seekins rings attached directly to the Picatinny rail machined into the upper. That configuration was only 3/4” off center. Is the 8.5” windage adjustment excessive? What do people typically see?

 

[_Windrider_]

I realize the windage adjustments needed when zeroing a rifle are dependent on the manufacturing tolerances of the rifle, scope base, and scope. Assuming the scope is optically centered from the factory, it’s basically how well the bore centerline is matched up with the scope mounting system. I just sighted in my Seekins PH2 in 7 PRC. Shoots well. Once sighted I had a 3 shot group at 0.35” at 100 yards. I didn’t bore sight the scope (no prior scope adjustments) but it was 8.5” right at 100 yards. That’s about 8.5 MOA. Once zeroed I don’t guess it matters. I have a Nightforce scope, Seekins 20MOA base with 5, #8 screws attaching the base to the action. I used some Burris XTR tactical rings I had from a previous rifle. Last year I sighted in a Seekins SP10, Nightforce scope, Seekins rings attached directly to the Picatinny rail machined into the upper. That configuration was only 3/4” off center. Is the 8.5” windage adjustment excessive? What do people typically see?

Your assumption that the turrets were zeroed is wrong. Just zero your windage turret accordingly.

 

[rmiked]

You mean the windage adjustment range may not be optically centered from factory? NF says they ship them in the center of the adjustment range. I adjusted it accordingly and it shoots well. I was just curious if others had seen that much adjustment needed. If the scopes aren’t optically centered, then the needed adjustment could be anything.

 

[chevy_man]

You mean the windage adjustment range may not be optically centered from factory? NF says they ship them in the center of the adjustment range. I adjusted it accordingly and it shoots well. I was just curious if others had seen that much adjustment needed. If the scopes aren’t optically centered, then the needed adjustment could be anything.

You're concerned over nothing. I have yet to see any scope from any manufacturer actually be set to perfect center out of the box. They're usually in the ball park, but since you didn't list a model I'll use the nx-8 as an example. They have 70-80moa of windage adjustment available. If they were 10% off center over 280-320 clicks I'd say they were pretty close to center.

The reality is that the adjustment is there to sight in with. The only time to get worried is when you completely run out of adjustment.

And while it's a complete guess, I'd assume they have some sort of alignment jig that they eyeball the reticle onto. I very much doubt they spin the turrets to both extremes and count the clicks back.

 

[CS95]

You're concerned over nothing. I have yet to see any scope from any manufacturer actually be set to perfect center out of the box. They're usually in the ball park, but since you didn't list a model I'll use the nx-8 as an example. They have 70-80moa of windage adjustment available. If they were 10% off center over 280-320 clicks I'd say they were pretty close to center.

The reality is that the adjustment is there to sight in with. The only time to get worried is when you completely run out of adjustment.

And while it's a complete guess, I'd assume they have some sort of alignment jig that they eyeball the reticle onto. I very much doubt they spin the turrets to both extremes and count the clicks back.

Actually most companies do center the reticle, but they don't do it by dialing to the extremes as that can be inconsistent with machining tolerances. They use a collimator and spin the scope while adjusting the turrets until the center is stationary while spinning the scope. Now, most companies likely have collimators that have the mounts centered to the collimator reticle. That way they just have to align the scope reticle and collimator reticle.

 

[CS95]

I realize the windage adjustments needed when zeroing a rifle are dependent on the manufacturing tolerances of the rifle, scope base, and scope. Assuming the scope is optically centered from the factory, it’s basically how well the bore centerline is matched up with the scope mounting system. I just sighted in my Seekins PH2 in 7 PRC. Shoots well. Once sighted I had a 3 shot group at 0.35” at 100 yards. I didn’t bore sight the scope (no prior scope adjustments) but it was 8.5” right at 100 yards. That’s about 8.5 MOA. Once zeroed I don’t guess it matters. I have a Nightforce scope, Seekins 20MOA base with 5, #8 screws attaching the base to the action. I used some Burris XTR tactical rings I had from a previous rifle. Last year I sighted in a Seekins SP10, Nightforce scope, Seekins rings attached directly to the Picatinny rail machined into the upper. That configuration was only 3/4” off center. Is the 8.5” windage adjustment excessive? What do people typically see?

Its probably the Chinese xtr rings.
Nightforce absolutely centers their reticles after QC as does most other reputable companies.

 

[chevy_man]

Actually most companies do center the reticle, but they don't do it by dialing to the extremes as that can be inconsistent with machining tolerances. They use a collimator and spin the scope while adjusting the turrets until the center is stationary while spinning the scope. Now, most companies likely have collimators that have the mounts centered to the collimator reticle. That way they just have to align the scope reticle and collimator reticle.

That would make sense. Likely the optical center isn't even the center of adjustment.

 

[waveslayer]

Not at all! I have several calibers for my MRAD and DT, there variance from one caliber to another can be that much. I am using the same scope each time, I don't even touch anything other than replacing the barrels. So yes, and once you zero, who cares. You assume that the Picatinny rail is perfectly straight etc.

 

[Ikeman83]

To give you an idea, 8MOA between the front ring and rear (assume a 3" mount seperation) works out to be:

8 = X >>> X = 24/3600 >>> X = 0.0066 inches of lateral offset from the bore axis.
3600 3


Simply put, this could be anywhere.

-Concentricity of bore to barrel
-geometry of barrel shank
-Fitment of barrel shank to receiver
-receiver geometry at shank
-receiver geometry at mount
-position of taps
-geometry of base
-geometry of ring
-fitment of scope in ring

Interestingly, every single one of those values can be in-spec but produce an alignment error due to stacking tolerances.

If you're well within the windage range of adjustment of the scope, it doesn't matter. If you're not, you can begin tearing down your gun, or get a mount with windage adjustment.

As an exciting side note, SAKO 85s have a front dovetail that's tapered from right to left, so the position of your front ring on that forward dovetail actually adjusts your windage.

 

[spife7980]

Is the 8.5” windage adjustment excessive? What do people typically see?

Not at all, its rare a new rifle scope set up will automatically be on a piece of letter paper at 100 yards for me.

 

[db2000]

Then there’s the variable of the ammo.

Man, talk about mental masturbation. Just sight the damn thing in.