
Smith & Wesson 617 .22LR Reduced Spring Kit with Extended Firing Pin – Precision Trigger Upgrade | TK Custom
TK Custom Reduced Spring Kit with Extended Firing Pin – S&W 617 .22LR Revolver
Unlock the full potential of your Smith & Wesson 617 .22LR revolver with TK Custom’s precision-engineered Reduced Spring Kit, now featuring an extended firing pin for enhanced reliability. Designed to deliver a smoother, lighter trigger pull while maintaining consistent ignition, this kit is the ultimate upgrade for target shooters and competitive marksmen.
Experience a significant reduction in double-action trigger pull weight—down to approximately 8.5 lbs—depending on your revolver’s endshake and headspace. The included extended firing pin ensures reliable primer ignition, even with the lighter mainspring. Dry firing is not recommended with this setup to prevent potential damage.
Key Features
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Availability: Ships within 4 business days
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REDUCED TRIGGER PULL – Achieve a smoother, lighter double-action trigger pull around 8.5 lbs, enhancing shooting accuracy and comfort.
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EXTENDED FIRING PIN – Ensures consistent and reliable primer ignition, compensating for the reduced mainspring tension.
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DROP-IN INSTALLATION – No gunsmithing required. Includes all necessary components and tools for a straightforward installation process.
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COMPLETE KIT – Comes with Wolff reduced power mainspring, 12 lb rebound spring, reduced power firing pin spring, extended firing pin, strain screw, blue Loctite, and Allen wrench.
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NO DRY FIRING – Dry firing is not recommended with this setup. Use snap caps to avoid potential damage.
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MADE IN THE USA – Proudly manufactured in the United States, ensuring quality and reliability.
Why Choose TK Custom?
At TK Custom, we specialize in enhancing revolver performance. Our Reduced Spring Kit with Extended Firing Pin is meticulously designed to improve your S&W 617’s trigger pull without compromising reliability. Trusted by competitive shooters and firearm enthusiasts alike, this kit offers a tangible upgrade to your shooting experience.
Spec Ops Profile
- Part Name: Reduced Spring Kit with Extended Firing Pin
- Compatibility: Smith & Wesson 617 .22LR Revolver
- Trigger Pull Reduction: Approximately 8.5 lbs (dependent on revolver’s endshake and headspace)
- Included Components: Wolff reduced power mainspring, 12 lb rebound spring, reduced power firing pin spring, extended firing pin, strain screw, blue Loctite, Allen wrench
- Installation: Drop-in; no gunsmithing required
- Made In: USA
*Quality you can see. Excellence you can feel.*
Free Shipping on orders over $250.00 in the USA only!
Smaller orders less than $250.00 are $9.95 for shipping.
No Free Return Shipping with Labor
No International Shipping, except to Canada.
$35.00
Canada - Priority Mail / NO Tracking Out side of USA

FREQUENTLY ASKED QUESTIONS
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Federal or Remington & others makes works the best with the .025 thick Full Moonclips, which fit all the .38/357 standard moonclip. They allow the cartridges to have some movement or wiggle so that they will fall right into the chambers once properly aligned. Winchester brass does not work at all as the groove width is too tight/small.
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Use this text block to discuss some commonly asked questions like shipping and returns, sizing, warranties, or product and company details.
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There is no SAAMI specifications for the extractor groove and each manufacturer makes them as they want. The following list gives you a great example. This is why the diameter size of the brass is critical to proper loading, unloading and fitment. Cartridge diameter too big and moonclip too small causes the moonclip to bend. The cartridge should rotate within their respective place and wobble slightly when all cartridges are loaded.
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If you are unsure about how to use moon clips for your revolver, or wondering which moon clip to use, call us. See the Contact menu tab.

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