Ruger's policy about mods is they will return the gun to factory specs, at your expense. Now, its a liability issue. If you made it unsafe, and they didn't correct it, they can be at fault for not protecting you from yourself.

I have a 10/22, a Mark II 22/45 and a Mark III.

I compete with my Mark II 22/45. It has a 4" bull barrel, and is pretty light. Probably too light. I shoot better with my Mark III 5.5" bull barrel. Heavier and better ballanced. You may have noticed that better target pistols can utilize barrel weights to make them more balanced to your specific needs. The S&W 41/46 use barrel weights, as does the Walther P22 series (I think the 3 and 4) Others do as well.