With reduced velocity I'd be hesitant to shoot the TTSX. On the other hand, I think the Accubond LR is a bit "soft" if the distance is short. I'd give thought to the regular Accubond or partition 165 grain. Both are soft enough to open with relatively low impact velocity remaining at 300 yards with the reduced launch velocity you're considering and yet will hang together with all the velocity a .308 can muster even at powder burn distance.
My current load for my Kimber Mountain Ascent in .308 is 44.5 grains of RL15 and 165 grain accubonds. It's predecessor, a Kimber Montana, shot it's best with the same bullet and 43.5 grains of RL15.
Tom
