JM625 Misfires

[RickK]

I installed a Wilson Standard Spring and went to the IDPA shoot.....Had a great time...most Fun I had with my Clothes on in quite awhile
I had 8 misfires out of 80 rounds. Really sucked. I came home and put a small shim under the main spring screw and went out back and fired the
misfires off with no problem. Ran a few more rounds and had one misfire. Monday the S&W replacement spring came in. I installed it and ran 30 some rounds, various primers WW,CCI, & Federal not one misfire.
Quite a stiff trigger pull in double action and the Serrated trigger really tore my finger up. I would say it's most likely 100% now. Especially after fireing my reloads with WW primers, before I had a 50% misfire ratio. Going to have to dry fire more to get my finger in shape.

Rick

 

[Tom C]

I installed the C&S extended firing pin and played with the springs on my 625JM, but I also pulled out the trigger and lightly took some very fine sand paper to the ridges on the trigger. It was really tearing up my finger. Now it is fine.

 

[Stainz]

I still think the problem is the original strain screw. Mine had been filed - and a 'stock' one fixed the problem. As I said, the smallish diameter end works into the hollow of the 'Power Rib' on the Wolff hammer springs, lessening the pre-load. The 'fix' I opted for in my new 617 last year, with a standard power Wolff leaf, was simple enough. I replaced the strain screw with an Allen headed SS set screw (6-32 x .5", I think... might be a #8!) from a hardware drawer at Home Depot - bagged 2/$0.56. I had measured the distance the tightened OEM screw held the leaf off the frame and duplicated that with the set screw. I then fired some rounds - unloaded the revolver, removed the grip, and unscrewed the set screw a half turn, reassembled, reloaded, and shot some more. When ftfs were noted, I screwed the set screw in a half turn and put a toothpick drop of blue Loctite on the threads. Thousands of rounds - and a year of lots of use later, still no ftfs. .22 rimfires are more persnickety to fire than the cf .45s, that's for sure.

I would put that lite Wolff spring in and a set screw. I was lucky, my 625JM works great with a new strain screw and the standard power Wolff spring.

Stainz