I recently purchased a used P239 and I'm in the process of ordering new springs for it.

I noticed that mainsprings run as low as 12lb. which is a good deal lighter that the factory 18lb.

I know a lighter spring can result in a lighter trigger but doesn't the mainspring slow the slide down on recoil as well?

The mainspring has nothing to do with slide velocity. You may be thinking recoil spring-the mainspring powers the hammer only.

Actually, the slide has to cock the hammer as it comes back, so a lighter main spring would mean a faster slide. I don’t know if it’s a meaningful difference, or even measurable, but there would be a difference.

Re the Wolff mainsprings (hammer springs). Buy the "SIG P239 RP HAMMER SPRING PAK". Has a 12, 14 & 16 lb spring.

I've played with Wolff spring kits on all of my Sig classic P-series. Generally, the middle weight works the best for me.

I use the 14# in my P239. It's a carry gun and is reliable. It has been tested with reloads and carry ammo. The 12# has occasional failures to fire. If yours is a carry gun, test it thoroughly with all ammo used.

Every guns is different, so don't take somebody else's word. With the three pak, you can try all of the possibilities your self. Note that when you reduce the weight for DA, it also lowers the weight of the SA. In some instances, you get a great DA and a too light SA. In addition the DA and/or SA may get a funky feel with the lighter spring. That's why the three pak is a good idea.

https://www.gunsprings.com/SIG...239/cID1/mID4/dID256

Good luck. Welcome to the forum.

quote:

Originally posted by Tusk:
Actually, the slide has to cock the hammer as it comes back, so a lighter main spring would mean a faster slide. I don’t know if it’s a meaningful difference, or even measurable, but there would be a difference.

All true. I tell shooters who have a difficult time manually cycling the slides of guns like the P220 to cock the hammer first to make it as easy as possible.

Mainly, though, is the mainspring’s effect on trigger pull weight, and Nipper did a good job of discussing that.

Thank you all for you responses.