Long Range Caliber to 1200 Yds

[Triple BB]

I've got three big bore long range guns. Two of them are 300 Rums. One has quite a few rounds through it and I'm mulling changing barrels to something smaller. Any suggestions on something with less kick that would make a decent pack rifle that would still knock down a deer or elk out to 1200 yds. Not wanting to change bolts, so it would likely be a magnum cartridge. Thoughts?

 

[elkaholic]

30 Sherman Magnum is the best one out there for all around performance and good brass. Another real plus is you can shoot 300 prc factory ammo in a pinch with great accuracy.
I run the 245 Berger at 3000' in my 28" barrel.
shermanwildcatcartridges.com