I own a couple - a model 700 and 7600.
I don't actually use them that much.
I have shot a few deer and they work fine.
Use a heavy bullet. Barnes X is only 85gr, but most are 95-100.
I like the Federal Premium 100gr Nosler Partition.
Anything in the lungs will do, but you have big heavy deer, so pick a deep penetrating bullet.
Cruise the Midway site and look at the reviews for 6mm.