Over the years I've found that there is a HUGE amount of variation in Sig's triggers.
I've dry fired, and live fired, many new and used Sigs at gunshows and matches, and have always been rather shocked that some of the triggers are simply as bad -- heavy, gritty, stagy -- as they are.
A few years ago I was looking at new 220s, seriously contemplating purchasing one. The first one I picked up had a so-so trigger. The next one had a HORRIBLE trigger, as did the third one at another dealer.
Yet another dealer had one with a so-so trigger, but the other one on his table had one of the finest double action triggers I've ever felt. It was smooth, even, and relatively light.
Unfortunately, his prices were almost $100 more than what the other dealers were charging for Sigs, so I didn't get the 220, and still haven't gotten one.
Some time later I helped a friend purchase a 228. We went through dozens of 228s at the Bealton show, and again found a HUGE variation on the Sig triggers.
He finally ended up with a lightly used gun for a very good price with a so-so trigger.
I never fail to play with the triggers on the Sigs at the gun shows I'm at, and the same holds true. It seems to break out that about 1/3rd of them are good, 1/3rd are so-so, and 1/3rd of them never should have left the factory with the trigger action they have.