Just ran the numbers for two of my loads, both using a 168g TSX - one for the .308 and one for the .300 Win Mag.
For the calculations I assumed each was zeroed for MPBR (Maximum Point Blank Range) using a 6" diameter target, meaning the bullet is never more than 3" above or below line of sight out to MPBR.
[Ballistic data omitted as it is included in my comments below]
If one accepts the .30-30 as an acceptable 100-yard elk rifle (and in my experience it is), one cannot dismiss the .308 as a 400-yard elk rifle.
The 150 tsx would give better ballistics (trajectory) than the 165 and still have good performance on elk
Powerguy –
While you are correct, the 165/168g bullets will carry more energy further down the road. They should also penetrate somewhat better due to their higher sectional density. Either one will do at 400 yards. My elk load is 165g North Forks with the 168g TSX’s as a backup.
.308 Win
150g TSX @ 2937fps (Hodgdon web site, fastest load)
244 yards = Zero
286 yards = MPBR, -3.0",1727fpe
300 yards = -4.4", 1727fpe
400 yards = -17.7", 1383fpe
.308 Win
168g TSX @ 2653fps (My load)
226 yards = Zero
266 yards = MPBR, -3.0",1800fpe
300 yards = -6.6", 1708fpe
400 yards = -22.2", 1466fpe
.300 Win Mag
168g TSX @ 3246fps (My load)
273 yards = Zero
321 yards = MPBR, -3.0", 2573fpe
400 yards = -10.6", 2302fpe
500 yards = -25.2", 1996fpe
700 yards = -75.3”, 1478fpe
Then for comparison –
.30-30
170g Speer FN @ 2200fps (My load)
100 yards = +3.0”, 1438fpe
182 yards = Zero, 1179fpe
213 yards = MPBR, -3.0”, 1079fpe