If you're using Winchester brass... work on up to 42.0 grains of the IMR 4895 with the 178's... you'll likely find that load will group much better than what you've got so far (not that you've done badly at all... just sayin')...
With Lapua or RP cases, use 41.7 grains of IMR 4895 with the 178's.
For your 165's, OCW (Optimal Charge Weight) in Winchester brass should be at 43.7 grains. Drop that by .3 grains for Lapua or RP brass.
With FC cases... reduce by a full grain of powder, as they're thick...
Dan