M1917 @100 yds

[CINDERS]

Check this chart out on sniper loads tested and the powder albeit in 308 and not 30/06 as I checked 3031 and it may be that that powder is to fast setting up different harmonics causing shot dispersion.
3 targets show a general central dispersion with 1 target dispersal low right I'd have a look at a slower powder.

I tried for a long time to drive my 6.5 x 284 at the speed U.S shooters were 2950 fps/140gn Berger VLD's it would not really group all that well dropped a 100 fps off the load and it all settled down.
But it took 1 barrel to work that out mind you that was with 4 different powders / 5 different projectiles / 2 different primers / 2 different cases / 10 types of jump and 2 of jams !