Don,
What you're saying then is you get a little more that 8 inches of spin drift at 800 yards or 1 MOA?
I think the problem I'm having with this spin drift is that it is not constant. The amount of drift increases as the rotational speed of the bullet decreases and therefore increases with distance.
So there really isn't an angle that you set your tang sight at that will compensate for the spin drift at all distances. That makes the only real way to deal with it being to know your no wind zero at each distance that you shoot, record that and have that in your note book along with your sight settings. That might work, but I ain't never going to get a no wind zero at 1000 yards!
Being that spin drift is caused by the air pressure on the nose of the bullet, which is sitting above and to the right of the line of flight (RH twist), I would think that changes in air density would have an affect on the amount of spin drift at any given time. Is that correct?
The variables can get quite deep.
I would really like to understand this subject better and I'd like to know how best to deal with it, correct for it, but as I feared in discussions of this sort the answer seems rather elusive. I think I'm going to do some math
and come up with a shim thickness that I can put under the right side of my sight base that will move me over to the left about 2-3 MOA and see what that does at 1000 yards to correct for the spin drift. I will of course have to reestablish my 200 yard no wind zero.
I don't see how doing this can hurt anything and I'm hoping it will make my windage adjustments at long make more sense. I know that it always seems that I have more left wind or less right cranked in than the conditions would call for.
I'll let you all know how it works out, but that's going to be a bit of a wait,