Do you have a Sig Manual? If not, go on-line and find out how to take a Sig Slide down to clean it, then do it. One big problem with some people "cleaning" guns is squirting a lot of crap into the firing pin hole to "lube it". This junk congeals over time/heat and slows movement. If you have to "squirt" something in there, use "Gunscrubber" or a auto brake part cleaner that cuts oil and grease junk. Flush it well !. Then use a little light lube like Rem Oil. Once ou have it all apart, check for "burrs", use fine emery paper to very lightly polish any detected flaws, lightly oil, and re-assemble. Never shoot Russian ammo in anything US(coating melts and causes jams). Hope this hepls. I carried a Sig P220 .45 for years as an LEO/Instructor and with a cleaned weapon never had any issues.