Left to right windage creep out to 800 yards?

[Kix]

I'm noticing that as I get further out past my zero I have to keep dialing in windage adjustments to the left. At 400yds it's only a couple inches and at 800yds it's a couple feet. What are your thoughts on why this is. It's always to the left that I need to adjust. If my scope cross hairs appear to be straight up and down on the receiver, but my scope is canted (twisted) to the right a bit, this could be causing this correct? I noticed when building my savage model 10fcp chambered in .308 that it appeared my scope base mounting holes looked off center, but I thought it was an optical allusion. Has anyone heard of those holes being canted to one side or the other or the base mounting off center of the reciver?

 

[CoryT]

If the turret is plumb over the bore, your adjustments should be straight up. It's possible to have a scope reticle that is canted in the tube, and if you have leveled the reticle instead of the turret, you can have this problem. Test the system. First, insure the turret is level, if the scope rail is canted, use the bolt lug rails to level the receiver first, then level the turret. Remove the knob and place your level on the actual adjustment screw.

Now, get a target about 6 feet tall at 100 yards. Set a dot for an aiming point near the bottom edge. After you are zeroed, use the dot at the bottom as the aiming point, then shoot a few groups of 3 shots with your 400, 600 and 800 yard dope dialed on. A plumb line held on the top group should run right through the dot and all groups.

You can also use any vertical line if you can mount the gun in a vise so you can dial adjustments and watch the crosshair move. Start with the aiming point at the top of the post or line, and as you dial, you'll see the crosshair move down, it should stay right on the line.

 

[wvlapua]

Spin drift is some of it. Do the tall target test it will answer your question.

 

[Kix]

If the turret is plumb over the bore, your adjustments should be straight up. It's possible to have a scope reticle that is canted in the tube, and if you have leveled the reticle instead of the turret, you can have this problem. Test the system. First, insure the turret is level, if the scope rail is canted, use the bolt lug rails to level the receiver first, then level the turret. Remove the knob and place your level on the actual adjustment screw.

Now, get a target about 6 feet tall at 100 yards. Set a dot for an aiming point near the bottom edge. After you are zeroed, use the dot at the bottom as the aiming point, then shoot a few groups of 3 shots with your 400, 600 and 800 yard dope dialed on. A plumb line held on the top group should run right through the dot and all groups.

You can also use any vertical line if you can mount the gun in a vise so you can dial adjustments and watch the crosshair move. Start with the aiming point at the top of the post or line, and as you dial, you'll see the crosshair move down, it should stay right on the line.

That's some damn good advise. I'll give that a go when I get back home in a few days. I'm going to have to run it like this for a few more days which is aggravating, but at least I'm hitting.. Thanks again!

 

[bodywerks]

Tall target test as mentioned above, and worry about your reticle being level, not your rifle, when shooting. I highly suggest a scope bubble level and true it to the reticle by lining the vertical crosshairs with a plumb Bob out at about 20 yards.

Sent from my SCH-I545 using Tapatalk

 

[Graham]

Left to right windage creep out to 800 yards?

Like Cory described: Box test the elevation to 10 Mils at 100y and then run a plumb line.

 

[Jon Lester]

How are you certain you are not canting the rifle when building a shooting position? Rotation Counter clockwise will yield left impacts.