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SIG MAINSPRING KIT Reviews & Ratings

Three, reduced power springs for tuning and smoothing felt trigger pull. Fits the newer P220, P226 and P229's that use a short mainspring with a plastic, hammer spring base insert. Contains 1 each of 17, 18, and 19 lb., reduced power, mainsprings. P220 factory spring is 22 lb. P226 and P229 factory spring is 24 lb.

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Reviews Summary

The SIG Mainspring Kit receives praise for significantly reducing trigger pull on various SIG pistols. Users report noticeable improvements, especially when using lighter springs, although tuning and additional modifications may be necessary to prevent issues like light primer strikes. Overall, it's viewed as a valuable upgrade for those looking to enhance their pistol's performance, especially with some extra work.

What Reviewers Are Saying

Improved Trigger Pull

75%

A majority of reviewers highlight the kit's effectiveness in reducing trigger pull weight, particularly in double-action (DA) and single-action (SA) settings. Many express appreciation for the substantial difference it makes in shooting comfort and accuracy.

Compatibility and Installation

45%

Users find the kit easy to install, noting that it fits well with newer models of SIG pistols. However, some mention the need for additional tuning and adjustments to achieve optimal performance.

Need for Additional Modifications

55%

Several reviews suggest that while the springs work well, they may require further customization, such as polishing or replacing firing pin springs, to ensure reliability and to avoid issues like light primer strikes.

User Expertise

30%

Reviewers with extensive experience working on SIG pistols emphasize that the kit can yield better results when handled by those with gunsmithing knowledge. It's seen as an excellent option for both DIY enthusiasts and professional gunsmiths.

Reliability Concerns

40%

Some users mention the risk of light strikes with lighter springs and recommend using heavier springs for duty or self-defense weapons. Overall, there's a consensus on the need to balance performance with reliability.

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Sig Hammer spring

Springs came in a timely manner and the fit was great

by LARRY H. on June 15, 2026

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WOW! Reduced Trigger Pull for Cheap!

The DA trigger pull on Sig pistols can be rather heavy. I used the 18 lb mainspring in this kit and it reduced my trigger pull substantially. I highly recommend this kit, it makes a HUGE difference.

Exactly as described

I've got a few Sigs and put the 18# in my P226 40 that has a 9mm exchange kit and the 19# in my P220R Carry, which was already modified with a dual adjustable flat trigger and a SRT kit. I'm pleased with the results.

Improves double action trigger pull

This item installs easily into the newer style mainspring housing. The difference between a well worn stock P226 mainspring and the 17lb reduced power spring is well worth the cost of this set. You may need to tune to a heavier included spring or add an extra power firing pin spring to make sure you dont get light primer strikes. I havent experienced anything like that, but passing on a topic of conversation that comes up when changing springs.

Works great

These reduced power mainsprings do as described. I'm currently using the 18lb spring as I had light primer strikes on CCI primers with the 17lb one. Next time I disassemble my slide, I'll replaced the factory firing pin spring with a reduced power one and retry the 17lb spring. DA is down to approx 9lbs and SA is a crisp 3.5lbs.

WOLFF SIG MAINSPRING KIT

This kit provides you with the proper spring for your special needs and all will reduce the trigger pull in DA and SA. A lot of parts polishing will make it smooth and the spring does the rest. I have always been able to get 100% ignition with the 17lbs spring but recommend a little heavier for a duty or self defense gun.