RE: .204 Ruger for small varmints
Years ago, the most accurate bullets you could buy were either .224s or .308s. Today, I dont that is still true. Considering the extreme competition the bullet companies are in, they all try to make the very best varmint bullets they can. Using cheaper components is really not a way to achieve the best accuracy, even in a .223. Now, it is true you can get very good military brass and save some money there. However, the cost of brass is really not that big a factor unless your losing it by using an auto loader. Decent bullets for the .204 and the .223 are probably similar in price. The powder charges will probably be similar. The primers will be the same. Basically, I think the cost of reloading GOOD ammuntion will be about equal between the .204 and the .223.
I have yet to meet a rifle that would not shoot better with custom tailored ammunition.