Best barrel for an AICS 1000M build

[Kryogen]

I have a rem 700P that I use with an AICS 2.0 as a 1000M build.

The barrel that I have in it is 1:12, 26 inches, and has .250 leade into the lands

I wonder if a 1:10 22-24 inches with riflings a bit closer would be a better option.
26 inches brings more fps, but more whip also.

Or, can the barrel be re-cut just a bit at the chamber to have a bullet closer to lands?

Best option?

 

[coyote]

For shooting at 1000M the longer barrels will give more speed so don't go to short , I just rebarreled one of my 308's and put a 28" on had a 30" before but decided to try a bit shorter and it works great.
I went with a 10 twist this time and there is no difference in performance from a 12 other than it will handle the heavier stuff now.

There should also be no issue removing your barrel and advancing the chamber a bit to remove some freebore.