you should buy about 4-5 different types of 180 grain loadings and choose the one your rifle is most accurate with.
if, by some stroke of luck, you also find some loads that feature 200 - 220 grain bullets, might as well try a couple of those.
i have not shot factory loads in any serious rifle of mine for years, but i do recall in a couple of guns they either shot the light mags well or they shot the custom well, but rarely did they shoot both well.
i can tell you, though, that chronographing many of the manufactured loads, hornadys loads run very, very close to 'as-advertised', and the federal loads were, quite simply, false. however, if a federal load shot well in my rifle, i would still use it, but i most definitely would not rely on a generated ballistic chart (which you shouldn't do, anyway). zero your rifle at 200 or 250 yards, and practice and you will be golden.
for my picks on factory ammo to look for: hornady (both custom and light/heavy mag), federal (premium and standard), winchester (supreme and super-x). from there, you will find one that you and your rifle just love.
also, since this is an -06 and you will be heaving 180's (or more) do not feel compelled to use partitions or barnes bullets or the like (unless they happen to shoot better than the standard fare - which is quite unlikely). game kings, pro-hunters, and interlocks have a fantastic rep for shooting well, and i can tell you they will put a whoopin' on whatever needs it - and they are relatively inexpensive.
best of luck to ya - i'll be chasing elk this fall and can't wait, either!