Duty/Carry Spring Kit for J-Frame Revolvers

If you carry a J-Frame revolver, you know the double-action trigger pull can be a real handful—especially when you’re trying to make quick, accurate follow-up shots. This Duty/Carry Spring Kit is designed to lighten that heavy factory trigger pull by roughly 3 pounds, making the revolver noticeably easier to shoot well without compromising reliability or safety. It’s a simple, drop-in upgrade that gives you a more manageable trigger for everyday carry or range use, without turning your revolver into a competition-only piece.

Will This Fit My Gun?

This kit is purpose-built for Smith & Wesson J-Frame revolvers. It fits the following models:

• Model 340, 340PD, 340 M&P
• Model 342, 342PD
• Model 360, 360PD, 360 M&P
• Model 442, 442 Pro Series
• Model 637, 638, 642, 642 Pro Series
• Model 649, 649 Pro Series
• Model 686 (J-Frame variants)
• Model 940

If you’re unsure about your specific model, give us a call—we’re happy to help you double-check.

Key Features

• Lighter, more consistent pull – Reduces trigger pull weight by approximately 3 lbs. over factory springs, making double-action shooting smoother and more predictable.
• Drop-in design – No fitting, filing, or gunsmithing required. Just swap the springs and you’re good to go.
• Maintains factory safety values – The kit is designed to keep your revolver’s safety mechanisms intact. No worries about light strikes or accidental discharges.
• Made in the USA – 100% manufactured in Phoenix, AZ, right here at home.

Install Difficulty

Difficulty: 2 out of 5 – This is about as straightforward as revolver work gets. You’ll need a small punch or a paperclip to remove the trigger return spring, and a small screwdriver for the mainspring. A pair of needle-nose pliers helps too. If you’ve ever changed springs on a J-Frame before, this will take you 10 minutes. If not, we’ve got a video walkthrough on our site to guide you through it.

Frequently Asked Questions

Will this kit work with my hammerless J-Frame (like the 442 or 642)?

Yes, it works with both hammerless and hammer-equipped J-Frames. The kit is designed for the internal lockwork, so the external hammer style doesn’t matter.

Do I need to replace the firing pin or other parts too?

Nope. This kit is a direct swap for the factory springs. No other parts needed. Just make sure your revolver is unloaded before you start.

Will this void my Smith & Wesson warranty?

It can, if you swap parts and something goes wrong. That said, this is a reversible upgrade—keep your factory springs in a baggie, and you can always put them back if you ever need warranty service. We offer a full warranty on the kit itself, so you’re covered either way.

Shipping & Warranty

We ship all orders within 1 business day from our shop in Phoenix. This kit comes with our standard satisfaction guarantee and a one-year warranty against defects in materials or workmanship. If something’s not right, we’ll make it right—just give us a shout.