Agree on the .270. I don't presently have one, but shot .270 almost exclusively for years. Still remember my most used load - 130 grain Sierra boattail over 55 grs H-4350. Killed a bunch of deer with that. I never shot anything bigger than a deer with a .270 but had a load worked out with the 160 gr. Partition Nosler that I'd have been (and still would) confident in for the bigger stuff. And to correct some thread drift here, my
270s were both steel and walnut beauties - an early Ruger 77 round top and a Remington 700 Classic. That 700 was crazy accurate and a friend-of-a-friend still has it. I had it set up just like the OP's Jack O rifle - 4x Leupold and all.