+1 on the OCW for load development.
2nd on the no need for small base dies. You are just overworking the brass.
In my 18", 1:8 twist, Wilson barrel, my best results with 77 gr. SMKs at mag length, L.C. brass, CCI 450 primers:
8208-XBR - 23.4 gr.
H4895 - 24.1 gr.
RL-15 - 24.7 gr.
TAC - 23.8 gr.
Varget - 23.9 gr.
