SDH: I'm not current on what factory chamberings are available in 204 Ruger, not much interested in factory rifles. Of those that I've had, quickly became disgusted with them & rebarreled with Krieger, Bartlein etc., chambered in benchrest cartridges. Are not Remington's, Savage's, Winchester's, Cooper's ( I know for sure) Kimbers and others available in 204 chamberings? So there are many choices to enter some of these match's with a factory rifle chambered in 204, but I seldom see them. Even at that, someone is free to build a custom rifle in 204 & compete in the custom class ( against the ppc's, BR's, and 22BR's), something else I've never seen. So, we're back to the original question as to the choice of 22BR or 204? If that choice relates to accuracy, then the 22BR is the logical one. If someone is more interested in the "splat" factor then the 204 may be their choice.