And you can shoot some even heavier bullets if the shape is right. Especially blunt shapes. Round nose for example. The 10" twist common in military rifles was a carryover from the Krag which fired 220 grain round nose bullets at around 2300 fps. Berger's tables show 12" is optimal even with their 190's, and those aren't blunt.
The old 10" twist is really too fast for best accuracy with 150 grain bullets and down. Your 12" should do pretty well across the board. For target shooting I have a preference for the 175 grain Sierra MatchKing in my 10" twist guns. You may be able to make both those and the new 155 grain Palma bullet work with your 12"? At shorter ranges, you'll likely find the 150 grain flat base Berger gives you the tightest groups out to about 250-300 yards.
Hunting bullets are not normally quite as precise as target bullets, but IME, both Sierra and Hornady make hunting bullets that work quite well on paper. Berger has them for extreme range. Again, a flat base will generally be easier to find a load for that shoots tight groups out to 250-300 yards or so, but the boattails will come into their own when you shoot farther.
