Re: 6.5 stw
I understand that the 6.5 STW is very similar to the 6.5-300 Weatherby.
With a 6.5-300 Weatherby Mag, a 30" barrel, 140 Bergers and 83 grains of H-870, I was getting 3,400 fps. Swap the 140 Berger for a 120 Ballistic Tip, and I'd get 3,500. IMO, these cartridges are really at their best with the heaviest (best BC) bullets around.
Shot slowly and mostly for groundhog and deer shooting, the throat lived for 750 rounds, then mandatory cleaning (or face high pressures) got too frequent and too hard to do. Still shot 3/8 moa when I took it back to the smith, just terrible to operate.
A .264 WinMag is much more enjoyable to shoot and maintain, not to mention cheaper. IIRC, a .264 can get within 150-175 fps with the 140's using 20% less powder and 10% less throat.
I have a "love/hate relationship" with this rifle, because it shoots like a laser and kills like lightning, but, man, it is ever hard on barrels and tough to get completely clean. Takes a lot of the fun out of it. Because I was already invested in custom dies and a few hundred rounds of prepped brass when I had it set back and re-crowned, I went back to the same 6.5-300Wby. Otherwise, I'd have gone to a .264.
I also have a 6.5-284 Norma and often wish it had a bit more power, which puts one right at the .264 level.
The beatings will continue until morale improves.