Up date on the RB 4" M10-10.
I did not find a longer strain screw and I confess I didn't go to the HW store for a grub screw. Instead I pulled out the little drawer into which I've dumped half a dozen or more S&W main springs over the years. I found the factory spring I had replaced with the Wolff which was giving me occasional miss-fires. I found a non-ribbed main spring that curved a bit more than the factory version and tried it in the K-frame. Fit fine although I have no idea what it came out of.
Anyway it wasn't until the middle of this week I got to shoot the gun again. The same hand load that caused problems before (10.5g 2400/158g Berry's plated FP) went off every time, for me and the other two guys I was with who wanted to shoot it. Miss-fire problem is solved and all is right in the revolver world...except now I need a way to carry this in the truck. Life is just one thing after another. Ain't I lucky. (smile)
Dave