Had one, nice shooter. Haven't heard of 204s being barrel burners. $1600 +/- sounds about right.

I've owned three #1s over the years in 30/06, 7x57mm, and 218 Bee and none of them shot MOA. From speaking with others it would seem that #1s either shoot or they don't and if they don't you will risk your mental health in trying to get them to. Personally I would choose a different rifle for any type of competition. As far as the 204 cartridge goes I can't see the point. To me this is just another in a long list of "designer" cartridges designed for use in the plastic rifles and which performs no better than a lot of cartridges that came before. If you want a smallbore cartridge I would stick with those using a .224 bullet because of the wide choice of bullet weights and the  superb accuracy that they give. Don't overlook the 222 Remington or the rimmed 225 Winchester which you can make from 30/30 cases. Both are super accurate and easy to load.

100 yds out to 300.

Sorry for the delay. Health issues. 
It would be for bench rest at 100 and 300 yds.

The 204 is an excellent varmint cartridge. My CZ 527 will shoot 3/4" groups at 200 yds but my son has it now. I doubt it would be a competitive benchrest cartridge as the  bullets are not special match quality and barrel life will be short. Also the Ruger #1 is not a good choice for a benchrest rifle. They are nice and I have several but they are not bench guns.

I had a Ruger #1 in 222 and it never on its best day would have competed in a benchrest match against a 6ppc.  I shot benchrest for a few years and you had better put 5 shots into 1/4" on a very windy day to hope to place.  If the wind was calm then the man with the best barrel usually won with a group around 0.100!  This was at 100 yards.  My first rifle I got from Shooter's Corner, a sleeved Model 700 and it would shoot good enough to improve my techniques but then I went with a Stiller Drop Port and my chance of placing went up considerably!  I guarantee that there are no 204 rifles at any major benchrest match and very few in some kind of a 22 caliber.  My 2 cents, no now my nickle's worth as we don't have pennies anymore.  Tom