The S&W Model 617 is built on S&W's "K" frame.
As such, it has the original S&W leaf spring action.
Only the S&W "J" frame small revolvers use a coil mainspring.
The S&W medium "K" frame and the "in between" "L" frame are very similar in size.
The "L" frame is generally a beefed-up version of the "K" frame, using a stronger, slightly more massive frame, and a larger diameter cylinder.
To simplify things, S&W made the "L" frame's grip area the same size as the "K" frame, so both sizes could use the same grips.
The differences between the "K" and "L" frames are more a matter of the frame being just slightly larger, but with more steel in areas needed to increase the frame's ability to handle large amounts of .357 Magnum ammo, and having a much more massive, larger cylinder.
The Model 617 internally is the same as the larger "L" and "N" framed S&W's and offers the same good trigger action, and the ability to be "tuned" by a revolver smith.
I'd take a 617 over any current .22LR revolver, especially a Taurus.
The reason people seem to prefer the 6 shot 617 over the 10 shot, lies in two areas.
First, the early 617 10 shot had an aluminum cylinder, and apparently these didn't stand up as well as hoped for.
The cylinder lock notches had a problem with battering of the softer aluminum.
Even though later guns are steel, the problems sort of "soured" the reputation of the 10 shot guns.
Second, getting a 10 shot cylinder to align PERFECTLY with the barrel is a LOT harder than with a 6 shot cylinder.
"Some" people have reported that the 10 shot 617 is sometimes slightly less accurate than the 6 shot guns, and often it's one or two of the 10 chambers giving the problems.
