I have a wildcat slightly larger than the .26 Nolser with that barrel. I don't have loading dies so the cases are more or less erratic but will work. I sent the first ones off to get some loading dies. Here is info for the first five I fired. This was at 300 yards.
After looking at some load for the .26 Nosler I decided to start with US869 @ 84.0 grains and stop at 87.0 grains. Based on the shooting results I could have used more powder.
95.0 produced a velocity of 3,450 feet per second.
95.5 " " 3,444 " Easy bolt
96.0 " " 3,460 " Tight in tight out
96.5 error "
97.0 produced a velocity of 3,533 " head had extractor mark
I was pretty excited when I could see, in the VX-6 4-24X52, the first two at 300 yards were touching. Shot #3 was out, but #4 was very close to the first two. In fact the three made a group of about 9/16"! The five shots still were okay at 2 5/8".