Have you used this in your STW?
I've mostly burned 872 in a load in my 270 win with a 130 grain blem bullet that wouldn't shoot with any other powder.
I currently have some 180's loaded with aa8700 for the 7stw. The rule has always been 93 grains aa8700 on a 140 in a 7stw, and 86 grains on a 175. Well, I loaded these to 87 grains on a 180, as the book went there. It's a bit stout.
This stuff is all basically burnable dirt, and the bore will be rather filthy after a couple boxes. I currently have wc872, aa8700, us869, rl50, and H50BMG in inventory for the overbore rifles. I run h50BMG as the only powder in my 7rum with 175 eld-x bullets. I plan on running more 872 when/if I burn out some of the rl powder I have.
I also burn rl50 and I 7383. Rl50 is about as expected for any 50 cal powder, but I 7383 is an odd duck. It may just be worth it for you to buy this at $10 a pound, or it may be an udder waste of time. I'd read on it before you buy any.
I am currently running I 7383 in a load in my 338win with a blem 185 grain bullet from Midway at 2700 fps. It shoots well, but having originally been in a spotter/tracer application it gets squirrely when you put the cobbs to it. I run it when I want to shoot the 338 without breaking the bank. When you can load 338's for under 50 a hundred, it's a bit easier on the wallet.