Greg,
I shot the 260 for silhouette competition for a few years and most folks shooting the 260 were using Varget, my go-to load for short range targets(out to 400 yards) was 36 grs of Varget, Sierra 107 bullets, in my factory barreled 700 Remington they liked to be near the lands but it may differ in your rifle.
Varget worked well enough that I estimate that a least 75% of the 260 shooters were using it a few years ago. I have since switched calibers and have not kept up with the current 260 trends so there may be something different in favor right now,but it always gave me around inch and one-half groups at 200 meters (220 yds). And plenty of retained energy, at some of the ranges where the rams were set solid on good sturdy rails I would use the 107's successfully on the rams at 500 meters.
drover