Hairy Ape,
Unless I'm misinterpreting what the hunting pamphlet says,You dont have to have a .50 cal. bullet to hunt elk with if the total weight is over 170 grains.

On page 14 it says
"a muzzleloading firearm used for all other big game must fire a single,non-jacketed lead projectile of nominal 50 caliber or larger,or fire a single non jacketed lead projectile of at least 170 grains"

I had the same discussion at work recently and it seems to be a common misconception or point of confusion.