[bermudaben]

Anyone know where to find a heavier spring for a 10mm Sig? FBI loads don't put a smile on my face like real 10mm ammo but I don't want my pistol to eat itself

 

[langwilliams]

Are you a member of any Sig groups? There's one on Facebook I'm in an those guys are all over stuff like this.

 

[darkwriter77]

If it's based on a similar Sig platform, like the P220, then perhaps there's a spring that will plug in there without any modification? It certainly LOOKS like an elongated version of a regular Sig. Y'know, sorta like how the Glock 20, 21, 40, and 41 all use the same factory spring; you can't really find any specifically for the 40 or 41, but there's lots of aftermarket 20/21 recoil springs, so that's what you use if you wanna install a stiffer or softer one.

 

[langwilliams]

Your post prompted me to read up on the 10 mm round....I didn't know the FBI throttled it back to make it more accurate...isn't the higher pressure charge the main advantage?

 

[bermudaben]

Yes that's there the .40 s&w came from and why the cartridge has all but died out. Any 10mm gun today is designed to shoot the prevalent "FBI" load which means putting full power ammo in it tends to over stress the gun. That's why I'm hunting for a better spring. I love this round how it was created.

 

[langwilliams]

it seems the .40 is loosing popularity too with the innovative 9 MM rounds available now....I hear a lot of police departments are turning in their .40's an going to 9 mm.

 

[darkwriter77]

The #1 reason a lot of departments are ditching .40 S&W in favor of 9mm (including the FBI and the US Army) is simply because of per-round costs. Secondary to that are the issues of felt recoil and accelerated pistol wear/shortened service life, which is largely an issue with pistols like the Glock 22 where they took a 9mm frame (the G17) and simply tossed in a different barrel and magazine and called it good - they even use the same recoil spring. The upsized 9mm models were never originally designed to handle those pressures or bullet weights, so it beats the frame apart over time, and specifically in the case of .40 S&W Glocks the cartridge is not fully supported by the chamber, so it's more prone to the occasional KaBoom or, at the very least, bulged brass casings (AKA "the Glock Smiley"). Strangely, the G21 is based off of the G20, which was designed to handle full-power 10mm right from the start (not the de-tuned "FBI load"), and that also has the same issue with not having a fully supported chamber, although those do NOT have a reputation for a short service life nor, to my knowledge, a lot of KaBooms ... although I don't know of any police departments that issue the G20 (or G29 or G40).

Anyhoooooo ... as far as Sig goes, I wouldn't worry about whether or not their pistol can handle factory 10mm loads from the "mild" to "spicy" range - Sig does make some pretty good factory 10mm cartridge loadings (their V-Crown ammo loads are even better than the good ol' Winchester Silvertips) - but it's when you get up into the "really hot" and "nuclear" range of things that I'd start to worry more about whether or not a stronger recoil spring would be advisable. Stuff from DoubleTap, Buffalo Bore, or Underwood in particular would be the ones I would avoid running through there without some beefing-up of the pistol ... and even then, I'd be wary of doing so if that Sig doesn't utilize a fully-supported chamber. With the barrel out of the pistol, drop a round into the chamber and see how much of the case head is exposed:

 

[langwilliams]

I read something about this in GLocks....something about "supported" or unsupported" rounds and mushrooming at the base.

 

[darkwriter77]

You get the idea.

Anyway. I've read conflicting details stating the Sig P220 10mm uses either a 20 or 22 lb. recoil spring. According to Wolff, 20 lbs. is the standard spring, and 22 lbs. is the next optional upgrade rating. If yours is green, then it's a 20 lb. recoil spring:

https://www.gunsprings.com/SIG-SAUER (SIGARMS)/P-220/cID1/mID4/dID6

 

[bermudaben]

Well underwood is my preferred "fun" ammo when I'm not shooting FBI loads. I collect all my casings and they do not show any deformation. As for the recoil spring; it's purple. I called Wolff and they do not make, nor have any suggestions about a replacement recoil spring.