I think 6BR would be that ticket for a varmint gun. Less powder, long barrel life and easy to load for. Lots of guys run slow twist (1-13t) in 6BR for varmints. That sends a 80gr bullet at 3100+ with 30 grains of powder. Faster twist barrels (1-8t) are for 105gr +/- at 2850fps. This is what I use for matches.
6creed and 6x47 are barrel burners. Don't waste to much time on brass either. It you want 6x47, simply neck down Lapua 6.5x47. Same with 6.5 creed to 6creed.
Hunt's Long Range has a recoil lug for the Bighorn Origin that will give it the exact same headspace as a TL3 so you could run shouldered TL3 barrels as well as Savage pre-fit barrels with a nut. If your looking at prefits, send me a PM and I can hook you up Mark Chanlynn. He is making his own prefit barrels now and they hammer like all his barrels.