I updated a couple of my older Sig P220s (one stainless and one blue) with SRTs and took the opportunity to play with the hammer spring weights. I believe that they both came from the factory with 20-21lb springs, but the stainless P220 was a bit lighter and smoother than the older blued.
The first gun was a all W. German blue P220 purchased in 1997 with a SN of G2764XX. It came from the factory with 11 / 4.5 lb DA/SA pull. I put a 18lb Wolff hammer spring in which brought the pull down to 9/4 lb. Definitely noticeable.
The stainless P220 was purchased in 2004 with a SN of G3359XX. The frame was made in Germany but the slide I believe is American. It started with a factory trigger pull of 9.8/4lb. I put a 19lb Wolff spring in which marginally improved the pull to 9/4lb. Not really noticeable.
Today, I fired 50 rounds of AE and 25 rounds of HST through both pistols. All rounds ignited just fine. I’ll shoot some Speer Lawman and Winchester next week and report back.