I have always been intrigued by the often complex, complete re-designs of the triggers for these guns - involving completely changing the geometry of the parts and/or pivot points, etc. I have also often wondered just how much of this was really necessary to accomplish the task of improving the trigger to at least an acceptable pull weight for a target pistol.
I had this idea getting bounced around in the ole' noggin for a while, and I finally decided to try it out and see what the results would be. The key is to reduce the two major friction points in the system - the trigger to sear contact point, and the sear to hammer contact point. The former was accomplished by installing a ball bearing into the top of the trigger lobe, where it contacts the sear. The safety detent ball is the perfect size, at 3/32" dia. It was set into the trigger lobe to a depth of 1/16". The ball rotates very freely and smoothly in this hole, and it is held in place by nothing more than a dab of grease.
Next up, the sear. First thing to do was to square up the top of the sear, so that the edge is square to the face of the sear. Next, the sear face was given a very gentle curvature, to reduce the surface area in contact with the hammer. The underside of the forward part of the sear is also polished, giving the ball bearing that was installed in the trigger lobe a smooth path to operate.
Last item in the mod is to install a 6-32 set-screw that has had a taper cut on the trigger-contact end. This screw adjusts the sear engagement, and as an added bonus, the taper serves as the over-travel. The red circle shows the gap between trigger and sear where the ball bearing now acts, and the green circle shows the point where the taper will control overtravel. The stock sear spring is used, as-is.
The safety was done away with, as many folks generally do. this allowed me to use the safety ball for the trigger mod, and to plug the holes formerly occupied by the safety, I made a couple of delrin plugs up, which press into the holes, and serve to eliminate much of the side-to-side slop of the trigger.
I don't have a proper trigger pull gauge, but using a fish scale, the trigger breaks at just under 2 pounds, or less than 1 kg. A lighter sear spring, or an adjustable one would probably serve to lighten this up even more, but I am more comfortable with the weight at it's current level.