Factory Sendero 1in9.25 twist at 4200 ft. elevation here. I shoot 168gr Barnes LRX on top of 82gr Retumbo. Barnes says this bullet won't stabilize in my rifle at this elevation, but it does just fine. My load is as the top end of safe, so if you use it, start lower and work up!
Good friend of mine uses 7828ssc for his STW, and he uses 150 grain bullets. If you stick in the 150 range, its a fantastic powder. Any heavier, and go with Retumbo, H1000, etc.
(Actually Retumbo sucks, give it to me and I'll dispose of it for you