I lost the extractor spring for my Sig P 320 Compact (the P250 extractor spring is identical). A lot of places are sold out of the springs, including Sig. Luckily I found a place that had them. When replacing the extractor spring, I thought that maybe I had another spring on hand that would work in a pinch. I found that a S&W revolver rebound spring will work. Now, I only installed it and fed and extracted a round with it, so didn't shoot it, so I'm not sure if it would hold up with continued use and under no circumstances would I use it on a Sig P 320 Compact that I had for serious defense, but for range use, I think it would work fine.