When I first tore into my used p85 I noticed that the slide stop had a lot of wear on it. The wear was from the barrel link and from where the trigger contacts the slide stop and pivots. I ordered a new slide stop and a P95 trigger from Ruger so I could do the conversion.
I cut out the area on the trigger to allow the barrel link clearance and then installed it and the new slide stop in the pistol. Wow, what a difference!
I noted that the front of the trigger comes into contact with the frame and keeps the trigger from traveling fully forward. I think this was a design fix as it does not hinder the operation of the pistol, but it does shorten the length of pull since the trigger is further back in the frame. It is very hard to tell, but I believe there is a difference in the geometry of the trigger that improves the function of the trigger. Essentially the surfaces that pivot together must remain the same, however if the dog leg that ties into the rest of the assembly was moved one or two degrees off from the p85 trigger it could make a huge difference in the function.
I have ordered new Wolff hammer springs to help lighten the action a little, but until they come in I have cut two coils off of my stock spring. The pistol still functions fine and I have not had any light hammer strikes. I will see how much of a difference the new Wolff springs make once I install them.
This is a great mod and has breathed new life into a surplus gun that I purchased for just over $200.00. I really did not care for the trigger before this mod, but now it makes it a contender as one of my favorites.