Actually it may surprise some to know that at 300 and 400 yards a 160 lauched at 3100 from a 7 Rem Mag will shoot flatter and have more energy than a 180 from a 300 Win Mag at launched at 3100.

My Barnes ballistics program shows the following.

.284" 160,BC of .468 at 3100fps muzzle vel, 200 yard vero

300 yards,Velocity:2491,Energy:2204,Trajectory:-6.17"
400 yards,V.......:2306.E.....:1889,Trajectory:-17.95"

.308" 180,BC of .410 at 3100fps muzzle vel, 200 yard zero

300 yards,Velocity:2411,Energy:2066,Trajectory:-6.42"
400 yards,V.......:2206,E.....:1728,Trajectory:-18.84"

Now....you could load a 200 gr bullet in the 300 with a similiar BC to the 160 gr 284" and launch it at 3100 from an Ultra Mag or possibly from a long barrelled 300 Weatherby and it will keep up with the 160 .284" bullet and maybe surpass it.The only tradeoff is recoil.This is why the 7mm Rem Mag is such a good all around cartridge for average shooters. It has the energy and trajectory and the recoil is hardly more than a 270 or 30-06.But...I still like my 300 Win better, I have both.