Last season I carried my scoped S&W 460XVR on a single point sling attached at the grip butt. It worked pretty well for carry but it does not assist your hold like a 2 point sling does. I carried it about 9 total days on various hunts with no issues. Long term I will probably mount a stud on the barrel lug for a 2 point mount. I would favor the single point over a holster for a big scoped gun, especially if you hunt above the ground as it will secure your gun from a possible drop.
"Therefore go and make disciples of all nations,... "
Handgun hunter since 1979 - haven't used a rifle since!
HHI member #992, NRA, SCI.