Without knowing your rifle, brass or primers, the best advice I can give is to start at 42.0 grains for both bullets. You may find the best groups right there, or 42.5, just by adjusting the COAL. It is a safe load even in USGI brass, so work up from there. In Remington or Winchester brass, LR primers, 45.0 is probably the best you can hope for the good combination of velocity, accuracy and safety. You may find the best COAL to be as much as 2.880 inches, which may be too long for your magazine, if you have a hunting rifle, rather than a custom bench gun.
With the 165 and 168 gr bullets, start at 42.0 and work up towards 44.5 gr. ( same for Varget or 4895 ) Don't fixate on trying to get 2,700 fps. Work for 2,600+ and accuracy by adjusting the COAL.
What is your goal here? The 155-gr bullets are for Palma matches. The 165-gr Partition is a hunting bullet for big game.
You will see all kinds of loads on the Internet, some in excess of 48.0 grains. Crazy. Don't go over 46.0 grains with 150 or 155 gr bullets without a chronograph. You will see where the MV increases stop.
Many thanks Southern. Rifle is 20" 1in 10 twist, 2.305 to the lands, so usually start seating at 2.290. With both bullets looking for sub moa at 100 yards, not trying to break any records, but was hoping to replicate the sort of accuracy I normally get with N140 but with slightly better velocities (45.6grains N140 was giving me about 2700).
No point in trying to hot rod, been there and it doesn't work, and I was also prepared to forgive the partition if it performed a wee bit less accurately than the Amax, as it would never see action beyond 250 yards.
45.0 gr RL-15 is an good load for 150-gr hunting bullets in many of my rifles, but with the longer 155 AMAX and 168-gr match bullets, that is getting to be too much powder in less space, for me. Besides, I think you will find great accuracy below 44.5 gr with both bullets.
If you are not shooting beyond 250 yards, you could shoot a 125-gr in matches and vanilla 150-gr flat base, like the Sierra PH, for hunting, with the same discernable accuracy as any match bullet made for 600+ yards.
Just using what we have in stock locally. Amax are cheap and plentiful, although I would have to say the 168 grain were probably winning on accuracy in my other 308. Velocity is definitely not the answer for accuracy. The partitions were really solely for use on stags.