...If canting the rifle gives a shooter a more solid hold, then canting can more than offset a POI shift introduced by the cant. Remember I'm only talking about canting the rifle about 1/4" from reticle to bore. If I read your post correctly, the device that you are using won't guarantee better than 1/8" error. If you zero at 100 yards, with a ¼" cant then you have about ¼ moa of error. I zero at 200 yards so my cant only introduces a ¼" error for every 200 yards.
Take the 100 yard zero as an example, shooting at 1000 yards. From 100yds to 1000yds the error is multiplied 9 times (9/4"). That's only a 2.25" offset at 1000 yards. Shooting a Federal 175gr SMK at sea level, a ¼ mph wind will blow the bullet off 2.4". There are just too many errors in the system to make a ¼" cant significant.
Lets assume that all of your data is perfect (atmospherics, aeronautical jump, spin drift, coriolis, variation in powder temperature, handloading variations, variation between turret & reticle). In order to repeatedly hit you POA at 1000 yards, you would still have to correctly judge the wind to within ¼ mph.
I'd rather gain a steadier hold and accept a ¼ moa offset that I can calculate. Of course my entire point goes out the window if you don't get a steadier hold by canting.
Actually, a reticle alignment tool can reduce the angular alignment error down to the accuracy of the spirit level. In the case of the RingTrue tool, that's better than 0.5 degree, which is equivalent to about 1/64 inch of lateral offset or less from the bore. In practice, less than 1/32 inch of offset is probably more likely. But that's just a minor point.
I agree the error resulting from a 1/4 inch offset is small - nearly a 1/4 MOA click at long range for a 100 yd zero. But if you don't know which direction it's in then it's really a +/- 1 click error, because it could be either direction.
My first question is: how do you know the reticle misalignment from the bore is 1/4 inch? Rifle cant is only one cause. There is also receiver/barrel misalignment, barrel curvature, and ring offset. Are you saying that you measured all of the them and the total reticle misalignment from the bore is 1/4"?
But wait a minute. 1/4 MOA click turrets are pretty coarse to begin with for long range shooting. Many shooters would prefer 1/8 MOA resolution turrets, but don't want to count that many clicks. Having 1/4 MOA click turrets is already a compromise. Now you're proposing that nearly +/- 1 click error is acceptable. For many long range shooters that much aiming error is not acceptable.
And that's just one source of windage error. I know your hypothetical case corrected for all ballistic errors, except for reticle misalignment. In practice, however, if I compromised on this source of error, then I probably ignored spin drift as well. Maybe I was a little hasty when I aligned the anti-cant indicator and it's off a degree. How do all these errors combine? Do I now have 2 or 3 clicks of error? In what direction?
In long range shooting, unless we eliminate all these seemingly small sources of error, we don't have confidence that they won't combine to make a more significant aiming error. It's all part of a discipline that long range shooters strive for because we know that we may not get a second shot.
I follow your argument for canting the rifle to improve your hold. I don't understand how just 1/4 inch of rifle cant can make the difference between a steady hold and and an unsteady one, but I'll accept that it's the situation you're in. You gotta do what you gotta do. It sounds to me like an isolated case, rather than a common one.
If it were me, I would find a way to hold the rifle steady without causing a reticle misalignment. I might use scope rings with an offset in the opposite direction. I might even modify my stock.
