I've load a fair amount for the 260. For a 120 gr. and up bullets, IMR 4350 and in that burning range is what the 260 likes for accuracy and velocity. 4064 should work good with bullets from 85 to 100 gr.. With bullets 120 gr and over you will lose about 80-100 fps compared to IMR 4350. As far as accuracy, you will just have to try and see, but the 260 give at least acceptable accuracy with most powder-bullet combinations. 8)
I use 42.5 gr IMR 4064 under a 168 Sierra Match-King in my M1A 308 for my NRA HI-Power rifles matches, and in my M700 Police Sniper with a Leupold Tactical scope--it is a one-holer at 100yd and will hold inside of 1 1/2 at 300! You can hotter to hunt with, but as a match/accuracy load in the 308 it can't be beat! You may to go up or down 1/2 gr depending on your barrel. 42gr barely functions my M1A bolt, 43 seems to shoot as well as does 44. No need. I've settled on my mentioned load. 4064 is the accuracy powder for teh cartridge. I've used 46gr 4064/165 Sierra Spitzer in teh 30'06 for hunting. Mild recoil-dead deer. It is not a supped up load by any means. Fun to shoot. Good luck.
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