Just my opinion.... but the DISC is much more versatile than the Bighorn.
Mike! Long time buddy. Shot my bull elk last week with the LeHigh's you recommended. Love those things!
CONGRATS! hearing about an animal down really makes feel good. That .452x265CF-HP is and has been an awesome bullet.
What is more versatile about the Disc Extreme?
I say that and totally believe it, in comparison with the Bighorn, the bolt alone adds a huge benefit in containing the blowback pressure versus the plunger of the Bighorn. The bolt is in many ways offers added safety to the shooter in that pieces of the cap or primer are mostly contained in the face of the bolt. If you were to get the Lehigh Primer adapter and install it in a FPJ bolt all materials would be contained. The ability to shoot a 3 forms of the Knight ignition system are also enhanced. You do have the ability to make the breech area totally clean with a NFPJ system (bare 209 primer).
I am sure there are other considerations but those pop up in my mind right away.
Again 'way to go on the elk harvest'!