I know this isn't one of the powders you have on hand but several years ago I did extensive load development for my Blaser R8 that I had shortened to 16.5" and added a Thunder Beast Arms ultra 7" silencer.
I found many combinations to work well for accuracy but one that stood out above the rest. I have now many hundreds of this load through my rifle and continue to be impressed. I don't use it on game beyond 600 yards but to that range it is deadly.
The load is with IMR 8208 XBR and 168 grain bullets, Hornady A-Max or ELDM, Sierra 168 tipped Match King or Berger 168 grain Classic Hunter. All are sub MOA but the Berger is just amazing many, many, sub 1/4 MOA groups and at 2670 fps avg and SDs, 5-7 fps.
The pic is of one of the better 5 shot groups, they aren't all like that but none over .5 MOA.
The charge weight is above any reloading manual so I won't publish it because it is safe in my oversized Blaser chamber but would not be safe in a SAAMI min spec chamber.
To develop this load, I noticed that as I approached the reloading manual max groups kept shrinking so out of curiosity I just kept going and found they continued to shrink. But I never ran into any pressure signs before they began to open up again. Where I settled is 1.5 grains above what one popular reloading manual lists as max.
To be clear, I am not recommending anyone do this, just sharing my findings for what has been my favorite short barrel loading for my short barrel .308. It has proven itself in the field and on the range.