Does anyone know how to improve the performance of a Sigma 40? I know i can replace the recoil rod and spring with a better one. I had the trigger adjusted by S&W. Is there anything else I can do improve this pistol?

The stock flat-wound recoil spring is superior to any aftermarket piano-wire recoil spring.
Based on my experience using Sigmas for about 15 years as loaners and trainers, I'd question your information.
The Sigma is extremely reliable in stock form as the defense gun it was designed to be. A bullseye gun it isn't.

Learn to shoot it and practice.

Have you read these notable threads on the Sigma?
http://smith-wessonforum.com/smith-w...ead-index.html

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Science plus Art

What OKFC05 said.


And extensive trigger polishing if you know what you are doing.

Improve the shooter

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Aim small miss small

Accuracy is not an issue and the shooter is not an issue. The my sigma 40 is a great pistol, in fact I can out shoot just about anyone using it. I just want to improve the performance of my SW40VE. Which I do with all my work horse and competition pistols.

Ummm, given that, what exactly do you want to improve?

I shoot USPSA and IDPA, and sometimes shoot a Sigma in SSP for club matches. My Sigmas are essentially stock, but carefully action polished and much used.
My experience is that an M&P is better suited for serious competition when the entry fees pass $100, and has many choices in sights and trigger versions. I shoot the M&P 9 Pro 5" in sanctioned competion, as do many.
However, the Sigma does not have much aftermarket support, and there is very little "improve the performance" available, depending on what you mean by that(?) You can get night sights. You can polish the action. Apex has a kit that lowers the trigger pull by not quite 2#.

The #1 reason people drop out of my IDPA matches is that they start cutting springs or some such and "improve" a perfectly good gun until it is no longer reliable.

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Science plus Art

I am looking to improve whatever I can. This particular pistol I just want customize what I can. I want to see what I can do to it and select which changes I want to make. Basically, I am trying to get ideas on what I can do.

What improvements do you want? The SIGMA is a very basic pistol and they usually work as designed without improvement.

If you want a lighter trigger pull or more accuracy, spend a couple grand and get a Performance Center pistol.

Ok here you go.

I will first say the modification of any firearm can render the firearm unsafe and may cause malfunctions within the firearm. All modifications and repair should be done by a professional gunsmith or manufacturer. Modified Firearms should not be used for carry weapons.

1.remove pigtail spring(this may cause reset issues)
2.remove outer spring(you may replace with cut down pen spring)
3.de-bur and de-edge sear and bracket(inside and out)
4.fully polish sear and bracket(inside and out)
5.replace striker spring with apex or wolff spring(wolff spring may cause light primer strikes)
6.fully polish striker sear
7.fully polish, straighten, and de-bur trigger bar
8.fully polish barrel
9.de-bur and fully polish barrel port of slide
10.de-bur and de-edge the underside of the slide at the ejection port
11.fully polish feed ramp
12.fully degrease and re-oil all internals
13.polish slide ears

I agree with you that any SIGMA with the modifications you suggest should not be used for a carry weapon. I would add that it should not be used for self-defense of any type. I would further add that the modifications you suggest will void the warranty and destroy all resale value, except if you choose not to disclose, which is dishonest, or if you have a very unsophisticated buyer.

So, a perfectly serviceable pistol in a very affordable price range is, by the modifications you suggest, turned into a pistol of questionable reliability that cannot be used for its intended defensive purpose. The SIGMA is good for defense and very basic plinking, and is not significantly improved by your suggested modifications, and in fact, because of reliability issues, may be significantly worsened. The SIGMA was designed to imitate the double action revolver trigger pull of the K frame and if you want a lighter trigger, get the M&P. If you want a tack driver, get a Performance Center 1911 or 945.

I didn't say the mods wouldn't make it perform better.



Although I'm not a fan of the wolff striker springs or first time gun owners doing these mods as soon as they get home from their LGS.

Lets's see if I have this right, you have a $350 gun, which off-the-shelf gives you 100% reliability, good accuracy, and you can out shoot almost anyone using it, but you want to "improve the performance"?

There are 1000's of guys with $1000+ "performance" guns which would be happy with 2 out of 3 of those!!!!

My performance upgrade recommendation would be more ammo and more range time to work on your weak areas.