My 617 6" 10-shot is quite accurate, earning me 526 points out of 600 in my last bullseye pistol match with open sights (I shoot the Metro Pistol League in Fairfax, VA, at the NRA Headquarters Range on Mondays). It's a little annoying to reload between the timed- and rapid-fire strings, but with my newly-purchased
DS-10-SPEED loader that shouldn't be a problem next Monday.
I've found that my 617 doesn't like Remington Thunderbolt .22 ammo so much (very dirty, actually binds the cylinder on the
breechface, preventing the cylinder from turning), but the other stuff seems to work pretty well.
Back when I was stupid about .22s, I would dryfire my 617--the firing pin was designed such that it wouldn't strike the chamber face if it was accidentally dryfired on an empty chamber. But that didn't prevent it from breaking after dryfiring too often--I should have just used spent casings like I do now for dryfire practice.
My 6" version is a bit muzzle-heavy, but that's a desirable quality to me. If I were to buy one again I might go for the 4" version.
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Can't comment on the Single Six, but I do want one. Loading a single-action revolver like that will probably prove to be even more of a pain, since there won't be any speedloaders available. I do know that Ruger says that the SS is safe to dryfire (and S&W says the 617 isn't safe to dryfire)...