I'd love to have one with a 6" barrelAfter I purchased mine, I asked the same question. The answer I received is this revolver was made to shoot steel matches as well as other action style matches. This is not designed for bullseye matches but should do well in them with different sights.
The barrel length was selected to facilitate quick drawing from a holster.
They are idiots and after the next election I fear we are about to get even dumber idiots of that is possible. Smart move by Ruger incidentally. They sold a ton of product up here as a result of indicating they added two tenths of an inch to the barrel to meet our gun laws (thanks California). Their catalog indicated same and it worked,Yes- Canadian citizens cannot be trusted with that most fiendishly horrific instrument of mass destruction, a 4-inch revolver.
Murder, mayhem, rioting, societal chaos, fracturing of the Commonwealth, overthrow of the government, the end of civilization as they know it, would all inevitably follow.
A 4.2-inch barrel, now, they're perfectly safe & docile with.
As Canadian politicians clearly recognize.