The numbers on the 140 gr accubond are a little better, and should work nicely. An sd of .287 with a bc of .509 will get you better downrange energy with the extra weight. I would sight it in at 2.5” high at 100, giving me slightly over 3” low at 300 with over 1800 ftlbs of energy (more if you are much above sea level). I don’t have any experience with this bullet, but if the 130 gr - 140 gr bullets in a .270 at similar speeds are ok by many, this should be just as good if not better in my mind.
With the 120 gr ttsx, I would try to keep my shots to about 300 yards, where it will have over 1700 ftlbs of energy. The sectional density of that bullet is .24ish which should work, given it shouldn’t lose any weight while penetrating. Sighted in 2” high at 100 gives me point and shoot comfort to 300 yards.
Which shoots better in your gun?
