I have worked with the 300 WBY extensively the past 20+ years. I think it is as good a long range thumper as you are going to find without doing something exotic. I never used many 150 grain bullets as the laser range finders make the velocity somewhat meaningless with the ability to dial in your drop. I have shot more 165-168s than all other bullets combined. I think my rifles use about 84-85 grain H4831 with a 165-168. I have a short throated chamber so my velocities with this powder charge will likely be higher than yours.
With 150s I had best luck with R19 and VV N550. I could get 3600+ out of my current rifle with 150s. Factory 150s were 3700 but are too hot considering my short throat.
7828 in NOT a good powder for 150s. You are better with H4350, H4831 or R19 if you want speed. R22 is decent but not quite as fast. Highest velocities are with n560 but with the outrageous prices they are getting for that powder now, I have discontinued using it.
165s were best at 3450 ish. This was easy with H4831 and N560.
Never shot many 180s. Shot some 200s a long time ago and used H870 @ 3000 fps in a 24" barrel. H870 is a horribly dirty powder. I would not try R22, 7838, H1000 or Magnum with 200s.
Interesting! I've been trying to come up with a load for 300 Wtby in a new to me custom shop 700. Been up to 85 gr H4831sc with 168 NBT but cant get over 3080 fps on the chrono. Factory Wtby ammo is running around 3250 avg. Any thoughts?
