I think I paid $1 each with shipping for 100 pcs of factory wby brass. My vanguard is the standard wood stock in 257 wby. It really likes the 115 nosler bt's with rl-22 and fed mag primers. I'm still seating them to the "standard" wby depth. Under an inch for 5 shots very consistently. I have to let it cool before shots 4 and 5, barrel heats very quickly. Shouldn't matter on a deer rifle, unless you're on a "cull" hunt. I put a timney trigger in mine, my stock trigger was horrible. Mine's never had a factory round down it, mostly because of the price of the ammo. I'm sure my handloads will fill the bill. I just need a deer tag now.
My roberts is an AI, and is built on a win 70, douglas fwt bbl with 1-9 twist. It prefers max charge of IMR 4064 and 115 nosler bt's in rem brass. It'll shoot 3 that nearly cut the same hole with the last 2 of 5 shot group coming out, but still under 1". If I let it cool after 3, the last 2 will stay in. The fwt bbl heats pretty quickly.
I usually suspect bedding with horizontal stringing, hard to say without trying some things first. It's a ruger, with I assume factory ruger rings? Are you sure the rings are tight to the receiver? If rings are tight, I'd look at the bedding again. Is the crown ok? Is it the standard model or the lightweight? Some thin barrels don't like to be free floated. My AI has a pressure point under the forend, shoots better that way than free floated. You could try the business card trick, keep adding business cards between barrel and barrel channel, and see if the groups get better?