I currently shoot a 458 win mag. custom built off a 1917 action, 26"barrel. shoots 3/8" groups at 100 with 500gr hornady. may play with it a little to extend my usual shooting range for fun. add muzzle brake, heavier stock. other than the very expensive Lost River bullets, who makes the highest B.C. bullet in .458? sounds funny? well people still shoot .458 bullets out of rolling blocks (45-70, 45-90, etc at very long ranges and the 458 win mag has more horsepower than these. I'll see.