Re: 7mm STW Velocity
TMR, 80 gr of Retumbo or H1000 with a 160 Accubond it is a very accurate load. It is also about the max load of either powder, 80.2 Retumbo & 80.7 H1000, so be careful. You should get 3100+ with this load. That is a pretty flat shooter and a heavy hitter with a 160 bullet, plus a .550 BC as well.
The STW in 9 twist (most STW's are 9 twist) will shoot the larger bullets better than the 140's. YMMV
The key with the STW is not to worry so much about velocity. If that is super important to you, then rebarrel to 7 RUM.
I think going to a 28" tube in STW is a better way to increase speed then lighter bullets.
STW is a great round and if you get the 140's to shoot, that's great. But, If you rebarrel and go with a 10 twist to stabilize the 140's I feel that you are limiting yourself to the rounds potential. A 9 twist will shoot up to 180's with no problem. If I wanted to shoot 140's I still would get a 9 twist and take my chances. This way if I wanted to load up for Elk or Moose I'm confident I could find a good one for a heavy bullet.
Best of luck with whatever you decide. STW is a fantastic round. Remember YMMV.
Member 7MM STW Club