First thing I do with any new to me rifle is check bedding. Barrel free floated and no stress in the action. Then shoot it just as it came, never know how well some poorly bedded rifle will shoot. Then if it doesn't go 1" or better, Float the barrel and bed the recoil lug and rear tang. To check the barrel, I use a piece of typing paper doubled over. After doing that I start developing a load for it. I don't believe that you can generally develop a good load for a poorly bedded rifle, some times but not often. Then to start loading I find the powder that give's me the fastest velocity in the manual and start with that powder. I start a few grains low and work up 11/2gr t a time.. Oh I also choose a heavy for caliber bullet in a big game rifle. I think the idea of a lighter bullet with a monolith bullet is a good idea. I don't use them but have seen a few and they sure look long. That extra length has to go somewhere and the only place it can go is into the case. I prefer bullet's seated to the junction of the neck and shoulder. if it's a lighter bullet I've read and I do seat min one cal depth. In magnum rifle's with big load's of powder I always understood to use mag primer's the ignite the powder properly. When I shot magnum rifle's I always did use magnum primer's.
BTW, The powder of choice doesn't always work, be ready to try another. My old 7mm Rem Mag liked N-205 and not much else. Just a hang up of an individual rifle but big case's need slow powder's. I tried H870 in that 7mm mag and didn't work at all. H-4831 was better but no where near N-205. Of course you can't get N-205 anymore!
Since you asked specifically for 180 ttsx here was our recipe that shot lights out when we were first testing a bunch of different bullets:
Norma case
Federal 215m
76gr RL26
3.600 (.040 jump)
3150FPS
****** as with any load start low and work up, this is what worked in our rifles and might not for you (but I bet it does)
As far as powders go try H1000, RL26, and N570 (26 and 570 will give better velocity)
We settled on shooting the Berger 215 though because we tend to shoot longer distances but the ttsx shot incredibly well. Stick with the 180 if you decide to stay with the ttsx, don't drop down.
