I haven't fired a Savage in .204 and I'm not sure what they use for twist rate. From what I've read on the net, I think they use the original "standard" of 1:12".
Some guys say the've had problems getting good stability with 1:12" twist .204s and are recommending faster twists for 40gr.
My Howa is 1:12" and my results so far have been good with 40gr Vmax but I haven't done any serious load development with any of the 39/40gr bullets yet.
Just using some loads picked out of a quick ladder test, I'm getting around 1.5" at 200yds with the 40gr Vmax. But those same loads are only grouping 2"-2.5" at 100yds...like the bullet hasn't fully stabilized out at 100yds.
For coyote hunting, 1.5"@200yd is good enough for me but I'm sure I'll fiddle some more to see if I can get smaller groups.
In the meantime, and as "break-in ammo", I've just been shooting the 32gr Vmax Hornady factory loads out of my Howa and it just loves em.
Once I got about 50-60 rounds through it, it settled into 3/4" @ 200yds and it'll one-hole @100yds. I can't complain about that for factory ammo!
I've had good luck anchoring yotes with the 32gr Vmax too. Got around a dozen of them with that rifle the past two winters and every one of em dropped like I stung em with a .22-250. My longest yote shot with the .204 was 375yds and it was a nice clean lung shot that turned his chest cavity to soup and he only ran about 3 steps.
By reading the forums, browsing the load data, and talking to local 204 shooters, I was pretty convinced that I'd want to use 40gr for yotes as well but after taking the 32gr into the field I'm impressed with their performance on yotes. I'm not a real avid long-range shooter though and I try to get my yotes in to 200yds or less regardless of what I'm shooting.
As for both wind deflection and trajectory, the 32gr Vmax is near identical to 50gr from the .22-250. The 40gr seems to buck wind like a 55gr .22-250 but it does drop more once you get past 300yds.
It means reading another forum, but there is a lot of good info (and I think a lot of "bench talk" too) over at www.204ruger.com
. That's where I got most of my ideas from when I starting brewing up loads for my rifle.