7mm weatherby 160gr or 150

[69firebird]

I'm running out of 150gr Nosler solid bases. I just loaded some 160gr A frames and got the best groups around 73 grains of H100 doing 2950fps mv. Grouping 1-1/2" I wasn't to happy. As I increased up to 75 my groups got worse with 100 fps faster mv. I have read that with 160gr bullets and 1:10 twist and weatherby free bore that the accuracy could improve again driving them faster.

The 150gr solid bases group sub Moa at 100 yards and 3200fps mv.

I've killed several moose with those 150s and plan on some elk too. Should I give up and go back reload some 150gr partitions/accubinds or sciroccos?

 

[69firebird]

I calculated my twist rate factor this morning with the 160gr A frames and SG is 2. And the same for the 150gr partition.

best group 73grs (mv 2952 avg)
-2954
-2946
-2960
-2956
-2948

Id like to get another 100fps at least but I must be doing something wrong.

Weatherby mk5 accumark, fluted barrel and brake

weatherby/talley bases and rings- swaro z3

Cartridge OAL is 3.360 (weatherby factory length) I've read some OAL of 3.48, I haven't checked that they cycle in the magazine that long.

CCI Br2 primers

shot of a bench with front solid rest and rear sand bag