Gonna load for a friend. Just got some retumbo. I did a search but haven't quite got the answers I was hoping for. Seems like some guys are getting some stiff loads compared to manuals...others seem to hit max about like the manuals.
I was thinking at 101 of retumbo and col at 3.600"

hey kranky, my barnes #3 manual doesn''t show retumbo, nether does nosler #5 so i went to hodgdon''s net site, they use a 165 gr sft-sp bullet, start load is 97.o grains for 3,241 muzzle vel. COL.3530 their max 103.0 compressed load,3414 M-V, starting load was 54,200 psi max was 62,300 they used a 24 inch pipe 1-10 twist , rem brass and remington 9.5 magnum primer. i think you picked a great powder,barnes recommends a 50,ooo jump with their bullets. pop from wyoming shoots a 300 remington ulta mag in a 75 sako may-be he can help. regards jjmp

YUP--got POPs help...he was getting real good velocity about 2.5 grains under max so I'm happy I was able to get his help!!