Nothing to add with regard to 0.204. Interesting caliber with a [Hornady 7th Edition] 32-grain pill at 4,100 fps up to a 45-grain pill at 3,800 fps using Winchester 748 (and other) published maximum data.
I do have experience after the purchase of a lightly used Ruger American in 0.308 and it is ALL GOOD NEWS. It was EASY to accurize.
Compared to my 30+year "Go To" deer rifle, a 0.277 Win. Mod 70 Featherweight, the American is:
a.) a little heavy (to me) for all day carry,
b.) a little louder as the barrel is shorter,
c.) threaded for a suppressor, with factory supplied screw-on, knurled, thread protector,
d.) superb in its repeatability,
e.) more accurate than my 0.277,
f.) "about the same" in velocity, PBR, and terminal energy, where, as a meat hunter, I am most concerned.
g.) made (and backed up) by Strum, Ruger, and Company, Inc., through their 70+years of practice in the manufacture of affordable quality firearms.
On a strong note for Ruger Customer Service, they supplied me a significantly improved (free) STOCK for the 0.308 American after I found nearly all of its pressure molded plastic edges as sharp as razor blades, cutting the hand to carry and especially when bench firing. That should have been caught in Quality Control, but got shipped and sold (not the only one), leading to their retooling for smooth edges in stock manufacture.