Keeping in mind that the .303 British was used extensively for all Canadian big game, any caliber that will destroy an elk's heart and/or lungs will put meat in freezers.
My preferred elk rifle is a Sako 7MM Rem Mag. But since I haven't hunted in 10 years due to shoulder surgeries, if I can hunt again, and I will give it a go next season, I will take my .308 Win. But if I can shoot my 7MM Rem Mag, I will use it. But I ain't risking another shoulder surgery to a magnum.
Good luck,
R
