I shoot my S&W 617 better then my Ruger KMK-512, much better trigger on the 617 despite having Volquartsen parts in the Ruger, and the grip angle on the Ruger simply don't work good for me.
But had I been really serious about bullseye shooting I'd get a real competition pistol, for me the Walther GSP works good.
I'd say the technical accuracy of the guns isn't much different, both the 617 and the Mk2 can put 5 or 10 rounds of decent ammo in less then a inch at 25 without any problem. The difference is that on the better guns you can actually use the accuracy.