When I first got both my M85's the trigger sucked. After a few hundred rounds have gone through it, it's a lot better now. Try marrying the trigger,sear, hammer. Put some EMPTY .22 cases in the gun and cock the hammer. Now apply forward pressure on the hammer and maintain said pressure while you pull the trigger. It's gonna be a heavy trigger pull but work through that 2 or 3 times. This process removes the little tiny burrs and edges on the internals, basically accelerated wear.
Now for the fun part. Pop the sideplate off and clean the internals. I took the entire gun apart and individually cleaned and oiled each part, but I've heard just hosing it with cleaner does the same job. LIGHTLY lube the pins and contact points. Close 'er back up with a dab of loctite on each screw (those things are a bear to find in the dirt, don't ask) and you should be good to go.
As far as additional dry firing, which will help the shooter and the trigger pull, just save your empty cases and use those as snapcaps. Hit them a few times and swap them out for fresh ones.
I've got a little over 500 rounds (too lazy to go look at the log sheet for the actual number) through mine, and it's got the best trigger of any revolver I've fired, S&W 10's included.
Wolff makes a spring set for the small frame Taurii that might be of interest to you. I tried them, but got light strikes so I went back to stock; might be a different story with rimfire though. Not sure if they're built the exact same, but if you're getting light strike problems, in the M85 you can remove the firing pin spring and cut a coil or two off to help improve reliability with lightened hammer springs.
I might still have those springs laying around in my parts box. If you want them and I can find them, you're more than welcome to them, just need an address.
