I put a full strength Wolff mainspring in my 4" 617, 10 shot and started getting lots of misfires even with the strain screw down tight. But, it feels a lot better in double action than the stock mainspring. I do not use it in competition, so the misfires really do not matter. I just go around the dial again and they usually go off the second time around. I was also getting a fair amount of lead spitting but a 'smith friend of mine opened the bullet entry point of the barrel very, very slightly and that made a big difference. I find the build up of lead around the top strap by the b/c gap annoying but that is what happens with copper washed lead bullets. I shoot 586/686 in SSR in IDPA and having a 617 to practice with is fantastic. All in all I am very happy with my 617.