I used WC-872 powder in my 7 RUM for a little while, then switched back to Retumbo. I was shooting this gun in the heat of the summer, and found the ball powder too temp sensitive.
I ran a short ladder with the 168 Berger.
Started at 100 gr @ 3369 fps and ended up at 103 gr @ 3550. This was out of a 9 twist 32" bbl. I settled on 102 gr @ 3400 as it gave me .3 to .4 at 100 and better than moa farther on out.
Switched back to Retumbo, 85 gr @ 3350 for better accuracy and less variation in the heat of the summer.
"Character is who you are when nobody is watching"