With a 10 twist, I'd be in 120 ttsx mode. Basically go with the 257 Weatherby mindset for it...... high speed point and shoot death ray.
I tried that in my rifle. But, the 120gr TTSX (per Labradar) leaves my barrel at an average velocity of 3,338 fps, and the 140gr TTSX leaves at 3,280 fps.
According to the ballistic calculator, at sea level (because of the 120gr TTSX’s lower B.C.):
* at 200 yds downrange, the 140gr/120gr TTSXs are going 2,794 fps/2,797 fps (basically, the same); and
* at 500 yds downrange, the 140gr/120gr TTSXs are going 2,166 fps/2,108 fps.
And, if both are sighted in at 1” high at 100 yards, they both are 33.5” low at 500 yards.
So, I don’t see any advantage for the 120gr TTSX. They both have very similar trajectories out to 500 yds, and the 140gr bullet is going faster after 200 yds. Might as well have the extra 20gr of bullet to hit the animal.
