I can think of two possibilities:

* Some change of geometry.

* A spring pretension.

The spring pretension seems more likely to me. But maybe there's another mechanism that I haven't thought of…

I recall a thread on this awhile back. You might try searching for it. I looked at the Armorer page and it's not there, but I'll let you look here (SIG Pistols).

There is a small spring that comes preloaded upon a set pin. The set screw (when tightened) tip increases the tension against the trigger mechanism as it is wrapped around the pin. I think the tension screw can be accessed by using an Allen wrench with the hole in front of the trigger guard at the base of the dust cover. If you wish to change or swap the spring itself, the trigger assembly is made of 15 or so itty bitty parts. These parts can't wait to jump out and hide under stuff, in the carpet, behind the bookshelf, etc. and can only be found after dispensing a substantial amount of swear words...

Thank you, .38supersig!

Yes sir. You're welcome.