I have rigs in both AR-15 and AR-10 platforms. My large game set-up is a Remington R25 in 7 mm08 with a Mk4 Leupold 3.5x10, and a RRA Match trigger with JP springs. Loaded with 140 gr. SST's at 2800 fps it's very effective out to 500 yards. I get consistent .5 MOA with my hand loads. Also have several rigs in the AR-15 platform that I use for varmint and 200/300 yard egg shoot competition. With the right set up and load development, they don't give up much to the bolt for midrange work.
"Let us speak courteously, deal fairly, and keep ourselves armed and ready"-T. Roosevelt
I shoot a m110 at work and I have got second round hits at 1300 meters. I would feel comfortable taking a deer at around 800 after that I am not sure it would have the power needed. Smaller game like coyotes definitely out to 1200.
Here's the AR-260 in it's current configuration. 4-14x50 IOR and Tango Down Bipod. Great bipod for prone, not a great one for bench work though, too tall and has metal feet. The second picture is the 300yds target I shot with it today.
Without the First and Second Amendments the rest of The Constitution is Meaningless.
I have shot 3 deer at 285 to 300 yds. with my Browning BAR in 30-06. I just ordered a 20 MOA Picatinny rail from EGW to put my Vortex 6-24x50mm PST FFP MOA scope with a custom turret made for my 6mm Norma BR. It looks like the ark of the two calibers may be within 2 inches of each other. I am going to test shoot it out to 400 yds. with the new setup to see if it will be accurate enough to use next year in Wyoming.
I'd rather not carry my 15 lb. 6mm Norma BR. and the 30-06 will give me a lot more poop at longer ranges than the 6mm.