I learned how to take apart my police trade in Model 10, and tried out the Wolff reduced power mainspring. It wasn't reliable at all, so I switched to a standard power Wolff. But I still had problems, so I changed back to the original, but I'm still having light strikes. I didn't have any problems when I first got it.

I've been using CCI primers, which have functioned fine in my other guns. And the ammo in question functions perfectly in another revolver.

Did I mess up the screw? I tried tightening it as best I could, but now it goes click instead of bang everytime.

What is the next best thing to try? New factory mainspring, new screw, or ??

Thanks

__________________
NRA Benefactor Member

At this point I believe that your best choice is to purchase a new strain screw. A lot of Police Armorers used their free time tuning the lockwork of various officers revolvers, so it's not unusual to find an ex police revolver with a strain screw that has been filed down. If that is the case with your model 10 a new strain screw will probably fix your problem.

Note, if you want to test the effect of a longer strain screw remove a primer from one of your fired casings. Then remove the anvil from the primer, this can usually be done by prying it free with the end of a paper clip. Then take that primer cup, clamp an appropriately sized drill bit in a vise point down, and tap the dimple out of the primer cup. Finally, slip it over the end of your strain screw and you have a cup shaped shim between 0.02 and 0.03 inch. That should provide more than enough tension to the mainspring to solve your issue.

or...if you have another K frame, just borrow the strain screw from it to see what happens. Otherwise go with what scooter123 says.
tcc

It's pretty hard to ruin a main spring, unless of course you bent it in a vise or something. More than likely it sounds like you've got a short strain screw, so that's where I would start. They are readily available at just about any of the usual sources like Brownell's, Midway, etc.

Chief38

Put a spent primer cup under the strain screw to give it a little more length and see what happens

That sounds like a great idea! I will grab a spent primer and slip it over the end of the screw (once I take out the insides of the primer) If that is successful I will get a new screw and see if I can make better use of the Wolff springs I bought. Thanks for the idea.

__________________
NRA Benefactor Member

"....so I changed back to the original, but I'm still having light strikes. I didn't have any problems when I first got it. "

Unless there was a shim in there to start with and it fell out un-noticed when you did the initial mainspring change,,something else might be the cause.

It's a good place to start searching for the problem in any case.

I tried the set screw, and I cranked up the trigger to about 10lb with a Wolf full power spring in. With the factory screw and trigger, it was running 9lb 5oz, and the Wolff full power rib spring with factory screw was less, around 9lb 2oz. The gun shot CCI primers flawlessly for over 100 rounds, so I think we're back in business with it.

I will grab a caliper and measure how long the screw is. I guess someone ground it down a bit in the past. I know it wasn't me!

Now I just need to watch the Miculek trigger job video and smooth it out a bit...

__________________
NRA Benefactor Member