The 7mm Remington Magnum is not the dragon slayer people think it is.
Neither is the 30-06.There is no magic cartridge.Bullet construction means far more than bullet weight as far as penetration is concerned.I have taken a lot of game with both 7mm and .308" bullets and the best penetration that I have seen was from 7mm- 140gr failsafes.I have seen the heavy 220gr .308" bullets expand too much to attain maximum penetration.