No questions there, the 308 hands down, I've killed too many elk with mine to want to experiment with my .500 at that range, the .308 is good past 250yds with a whole lot less recoil and is flatter shooting.
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The 325gr XPB has a BC of .228, that poor BC makes it a 200yd elk load since it drops below the accepted 1500ft/lbs energy for elk, it would be 300yd load for deer tho, if you have a range finder with ya and know the actual trajectory which would need to be shot at so you aren't relying on calculated data.
The 168gr TSX has a BC of .404, I get 2650fps in my .308 Ultra with it and a near max load of Varget, you can see from the table below, the .308 has sufficient energy at 300yds.
Tim
Trajectory for Barnes .500 dia. 325 gr. XPB at 2100 Feet per Second At an Elevation Angle of: 0 degrees
Ballistic Coefficients of: 0.228 0.228 0.228 0.228 0.228
Velocity Boundaries (Feet per Second) of: 1120 1120 1120 1120
Wind Direction is: 0.0 o'clock and a Wind Velocity of: 0.0 Miles per hour
Wind Components are (Miles per Hour): DownRange: 0.0 Cross Range: 0.0 Vertical: 0.0
Altitude: 500 Feet with a Standard Atmospheric Model.
Temperature: 59 F
Data Printed in English Units
Range Velocity Energy Momentum Drop Bullet Path Wind Drift Time of Flight
(Yards) (Ft/Sec) (Ft/Lbs) (Lb-Sec) (inches) (inches) (inches) (Seconds)
0 2100.0 3181.9 3.03 0.0 -1.5 0.0 0.000000000
25 2016.1 2932.7 2.91 -0.25 0.58 0.0 0.036450403
50 1934.2 2699.3 2.79 -1.04 2.12 0.0 0.074431067
75 1854.4 2481.2 2.68 -2.41 3.07 0.0 0.114033048
100 1776.8 2277.9 2.56 -4.41 3.4 0.0 0.155352119
125 1701.6 2089.1 2.46 -7.1 3.04 0.0 0.198487126
150 1628.9 1914.5 2.35 -10.54 1.93 0.0 0.243538298
175 1559.0 1753.6 2.25 -14.8 0.0 0.0 0.290606026
200 1491.9 1606.0 2.15 -19.95 -2.82 0.0 0.339788759
225 1428.0 1471.4 2.06 -26.08 -6.63 0.0 0.391178312
250 1367.5 1349.3 1.97 -33.27 -11.49 0.0 0.444856162
275 1310.7 1239.5 1.89 -41.63 -17.52 0.0 0.500888210
300 1257.8 1141.5 1.82 -51.25 -24.81 0.0 0.559316717
Trajectory for Custom .308 168gr Barnes TSX at 2650 Feet per Second At an Elevation Angle of: 0 degrees
Ballistic Coefficients of: 0.404 0.404 0.404 0.404 0.404
Velocity Boundaries (Feet per Second) of: 2650 2650 2650 2650
Wind Direction is: 0.0 o'clock and a Wind Velocity of: 0.0 Miles per hour
Wind Components are (Miles per Hour): DownRange: 0.0 Cross Range: 0.0 Vertical: 0.0
Altitude: 500 Feet with a Standard Atmospheric Model.
Temperature: 59 F
Data Printed in English Units
Range Velocity Energy Momentum Drop Bullet Path Wind Drift Time of Flight
(Yards) (Ft/Sec) (Ft/Lbs) (Lb-Sec) (inches) (inches) (inches) (Seconds)
0 2650.0 2619.2 1.98 0.0 -1.5 0.0 0.000000000
25 2595.8 2513.1 1.94 -0.16 -0.08 0.0 0.028596159
50 2542.2 2410.4 1.90 -0.64 1.01 0.0 0.057792431
75 2489.3 2311.1 1.86 -1.45 1.77 0.0 0.087606592
100 2436.9 2214.9 1.82 -2.62 2.18 0.0 0.118058185
125 2385.1 2121.8 1.78 -4.15 2.23 0.0 0.149167376
150 2334.0 2031.8 1.74 -6.06 1.89 0.0 0.180954629
175 2283.6 1944.9 1.70 -8.37 1.15 0.0 0.213441238
200 2233.7 1860.9 1.67 -11.1 0.0 0.0 0.246649675
225 2184.4 1779.7 1.63 -14.27 -1.59 0.0 0.280603593
250 2135.7 1701.2 1.59 -17.89 -3.63 0.0 0.315327661
275 2087.6 1625.5 1.56 -21.98 -6.15 0.0 0.350847405
300 2040.2 1552.5 1.52 -26.57 -9.17 0.0 0.387189160