Miroku Winchester 1866 and 1873 Heavy Duty Firing Pin

Description
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Heavy-Duty Firing Pin for Miroku Winchester 1866 & 1873 Rifles

Increase the reliability and service life of your Miroku Winchester Model 1866 or 1873 rifle with the SliXprings Heavy-Duty Firing Pin. Precision-machined from premium MIL-SPEC alloy steel, this upgraded firing pin is engineered to withstand repeated firing cycles while providing dependable primer ignition.

Unlike the factory firing pin, the SliXprings design incorporates a radiused shoulder that helps reduce stress concentration at one of the most common failure points. This innovative geometry distributes impact forces more evenly, significantly reducing the likelihood of firing pin breakage and extending service life.

Heat-treated for maximum durability and precision manufactured for an accurate fit, this firing pin is an excellent upgrade for Cowboy Action competitors, recreational shooters, and anyone looking for increased reliability from their Miroku Winchester rifle.

Features & Benefits

Heavy-duty replacement firing pin for Miroku Winchester rifles
Radiused shoulder design reduces stress concentration
Helps prevent firing pin breakage
Manufactured from premium MIL-SPEC alloy steel
Comparable material used in military-grade M16 and AR-15 components
Precision heat-treated for exceptional durability
Promotes reliable and consistent primer ignition
Designed for long service life under repeated firing cycles
Proudly Made in the USA

Compatibility

✔ Fits

Miroku Winchester Model 1866 rifles
Miroku Winchester Model 1873 rifles
Factory and competition rifles requiring proper fitting

✘ Does Not Fit

Uberti Model 1866 rifles
Uberti Model 1873 rifles
Original Winchester rifles
Other manufacturers unless specifically listed

Important:
The SliXprings Heavy-Duty Firing Pin is intentionally manufactured slightly oversized to allow precision fitting for individual rifles. Due to normal manufacturing tolerances and previous action work, fitting by a qualified gunsmith or experienced rifle tuner is required. This is not a drop-in replacement.

Why Upgrade?

✔ Radiused shoulder helps reduce firing pin breakage
✔ Stronger than typical factory firing pins
✔ Reliable primer ignition
✔ Heat-treated for exceptional durability
✔ Designed for high round-count competition rifles
✔ Precision engineered for long-term reliability

Installation Notes

Requires fitting for proper operation.
Not intended as a drop-in replacement.
Professional installation by a qualified gunsmith or experienced rifle tuner is strongly recommended.
Designed to accommodate normal manufacturing variations between individual rifles.

Whether you're maintaining a competition rifle or replacing a broken factory firing pin, the SliXprings Heavy-Duty Firing Pin delivers improved durability, dependable ignition, and long-term reliability for your Miroku Winchester 1866 or 1873 rifle.

19 Product Reviews - Average rating 4.9 / 5 (Show All)

Review

Craig - 05/20/2026

Worked great

The Only Miroku Firing Pin

Hawk Eyes Hudson - 03/30/2026

Yes Folks this is a drop in part. I have never had to do any adjusting or fitting for this part. Everyday lightened firing pin springs works just fine. Have I ever had one break. Who's any brand anything has not broken at some point. These last a long time. Buy a two! One for backup!

Good Upgrade

Texas Red - 11/02/2024

So few upgrade parts are available for Winchester Miroku 83’ rifle. Feel get better ignition with this part

Looks Better

Greg Rorabaugh - 10/23/2024

Ordered Firing Pin and Lightened Trigger Sping. Installed both with Noticable improvement!!

So nice I ordered another set.

GERALD DAVIS - 08/11/2024

These springs and firing pins worked so nice on my Miroku Winchester 1873's I ordered more sets as spare parts.

Very happy!

GERALD DAVIS - 07/04/2024

I had gotten some of the springs and pins. I had been putting off doing a spring. I found a utube video on disassembling a Miroku. It went easier than I thought. I did both of my rifles this morning, springs and pins. I was glad once again I had my screw driver bit set. The lightened spring makes a huge difference in closing the lever. I am very happy. Great products!

Owner

Jim Moore - 01/04/2024

Fire pin worked great, solved light strike issue in 66.

Spring worked GREAT!!

Steve - 10/17/2023

Replaced my factory spring. Worked like a charm! Much easier and quicker lever action. Highly recommend.

Miroku Firing Pin Trigger Safety Spring

John Duane - 08/01/2023

Both easy to install and work fine. Big improvement with the lighter trigger safety spring.

Lightened Trigger Safety Spring

John T. - 02/21/2023

Product was as represented, was simple to install; and, significantly reduced trigger safety pressure for cowboy action shooting. Definitely improves the Miroku lever action!

Miroku 1873 44-40

Richard Wilson - 12/19/2022

Installed this Pin and Safety Spring. I could tell it was smoothing the lever action. Never fired a shot. Went to a Cowboy Action Event and my other rifle jammed.. Bad Ammo! I went to my Miroku backup. Worked like a charm. 10 - rounds on a Nevada continuous sweep, No Problems!

The Cats Meow!

Hawk Eyes Hudson - 10/23/2022

The firing pin fit like a glove with no fitting. The safety lever spring now allows me to set my lever even quicker and I can adjust and lighten the tension on my trigger main spring. This makes the trigger oh so much smoother. Don't adjust out to much tension or you will get light primer strikes. If you do just kick that trigger back and try again. Later you can adjust for more tension to relieve that problem. That's the Cowboy Way!