I will add that I do not subscribe to the 1" at 100 MEANS 10" at 1000. That has not been the case for me or anyone I know who has done it, on a repeatable basis.
I've shot 2 one hole groups with my 7mag while in Wyoming from a bench. That's 6 shots. Backed up to 300 yards and got one group at 1.3" and another at 3.6" (another 6 shots). An hour later, shot at 500, 800, and 1000. My 2 three shot groups at 1000 yards were hardly impressive: one was about 14-15" and the other was around 9". That is not consistent.
Put the target back at 100 yards and got a .254 with the last 4 shots I had.
So many things can change from your muzzle to the target at 1000 yards, namely wind.
I admire those who can get those tiny little groups at 1000 yards, meaning sub MOA. I haven't been able to do it on a regular basis. They are better shooters, probably have more trigger time, and likely have better built rifles than me, and it wouldn't surprise me if they know some reloading tricks that I have yet to figure out.