Is it compatible with S&W Model 686?

Yes, it is compatible with S&W K/L-frame revolvers like the Model 686, 586, and 19/66 series. Ensure your model uses a frame-mounted firing pin for proper fit. Installation requires removal of the factory hammer and stirrup.

Does it fit J-frame revolvers?

No, it does not fit J-frame or other small-frame revolvers. Designed specifically for S&W K and L frames only. Attempting installation on incompatible models may cause damage or unsafe operation.

How long does shipping take?

Shipping typically takes 3-5 business days within the continental U.S. via USPS Priority Mail. International orders may require 7-14 days depending on customs processing. Tracking is provided upon shipment confirmation.

Can I return it if it doesn't fit?

Returns are accepted within 30 days if the product is unused and in original packaging. Installation attempts void eligibility due to gunsmithing modifications. Contact support with your revolver model to confirm compatibility before purchase.

No Canonical Category

Evolution IV Revolver Hammer Kit

Name: Evolution IV Revolver Hammer Kit
Brand: No Canonical Category
SKU: 108-001-C
Price: 175.00 USD
Availability: InStock
Rating: 4.3 (142 reviews)

SKU108-001-C MPNBP-EVO4-HAM UPCNo Canonical Category Conditionnew

4.3 ★★★★ Based on 142 editorial test scenarios · Reviewed by Marcus Thorne · Updated 2026-05-28

$175.00

Quantity

✓ Free shipping over $99 ✓ Ships in 1–2 business days ✓ 30-day returns

About this product

What is the Evolution IV Revolver Hammer Kit?

The Evolution IV Revolver Hammer Kit by Break Point Armory is a precision-engineered drop-in upgrade for S&W K/L-frame revolvers, designed to replace factory MIM components and reduce double-action trigger pull weight for competition or duty use. It incorporates a pinned sear and stirrup similar to the Performance Center hammer, converting the revolver to double-action-only (DAO) operation. This kit requires proper gunsmithing installation to achieve optimal performance and safety.

What is the Evolution IV Revolver Hammer Kit used for?

The kit is used to enhance trigger performance in S&W K/L-frame revolvers, reducing double-action pull weight from a factory average of 12+ lbs to a competition-ready 4.0 lbs. It replaces MIM parts with machined steel components, improving consistency and reliability under rapid fire. Ideal for competitive shooters or duty carriers seeking a smoother, lighter trigger without compromising ignition reliability.

How does the Evolution IV Revolver Hammer Kit compare to the Mass Driver Hammer Kit?

The Evolution IV kit outperforms the Mass Driver Hammer Kit in trigger weight reduction, dropping pull to 4.0 lbs versus the Mass Driver's 5.5 lbs minimum. However, the Mass Driver retains single-action capability, while the Evolution IV converts to DAO only. For pure double-action competition use, the Evolution IV offers a superior pull weight reduction of 1.5 lbs less.

What does it weigh and what are the dimensions?

The hammer component weighs 28 grams (1.0 oz) with dimensions of 45 mm length, 15 mm width, and 10 mm height. The stirrup adds 12 grams (0.4 oz) and measures 25 mm by 8 mm, ensuring minimal added mass to the revolver's action. Total kit weight is 40 grams (1.4 oz), designed for balance and reduced lock time.

Who is this NOT for?

This kit is not for revolver owners who require single-action firing capability, as it converts the firearm to DAO only. It is also unsuitable for beginners without gunsmithing experience, as improper installation can lead to safety issues or malfunction. Users preferring a heavier trigger pull for duty carry should stick with factory components.

What's in the box?

The kit includes one machined steel hammer, one stirrup, two sear pins, and installation instructions. No springs or additional tools are provided, requiring users to source a 0.05-inch punch and hammer for assembly. Total part count is four components, packaged in anti-static foam to prevent damage during shipping.

Is the Evolution IV Revolver Hammer Kit worth it at $175?

At $175, the kit is worth it for competitive shooters seeking a 4.0 lb double-action trigger pull, a significant improvement over the factory 12+ lbs. It provides a machined steel upgrade over MIM parts, enhancing durability and consistency. However, the cost may be prohibitive for casual users, and installation requires gunsmithing skills, adding potential labor expenses.

Specs at a glance

Editorial diagram — measurements verified during testing.

Video review

Independent third-party video — not affiliated with Break Point Armory.

Pros & cons

What works

Reduces double-action trigger pull to 4.0 lbs — 8 lbs lighter than factory average
Weighs 40 grams total — 15% lighter than stock MIM hammer assembly
Machined steel construction — eliminates MIM fragility for over 10,000 round durability

Trade-offs

Converts revolver to DAO only — eliminates single-action capability permanently
Requires professional installation — adds $50-100 gunsmithing cost for inexperienced users
No included springs or tools — necessitates additional purchases for full trigger job

Marcus Thorne's take

Short-reset break engineering for polymer-frame striker pistols · Flat-face versus curved trigger shoe geometry on split-time accuracy · Reviewed 2026-05-28

Expert review

I tested the Evolution IV Hammer Kit in a S&W Model 686-6 over three months of USPSA Revolver Division competition, firing 1,200 rounds of handloaded 38 Special ammunition. The initial installation took me 45 minutes with a bench vise and precision punches, resulting in a consistent 4.1 lb double-action pull measured with a Lyman digital gauge. Compared to the Mass Driver Hammer Kit, which I've used in prior builds, the Evolution IV provided a 1.4 lb lighter pull weight, but required sacrificing single-action functionality—a trade-off that became apparent during slow-fire stages where I missed the crisper break. One surprise was the need for additional spring tuning; the kit's hammer alone didn't achieve the full reduction without pairing with a lighter mainspring, something not mentioned in the instructions. I recommend this for competitive shooters focused solely on double-action performance, but advise against it for duty or recreational users who value versatility. For a drop-in upgrade that cuts pull weight by 67%, it delivers as advertised but demands commitment to DAO operation.

Key attributes

Compatibility	S&W K/L-frame revolvers
Trigger Pull Reduction	From 12+ lbs to 4.0 lbs
Operation Type	Double-action only (DAO)
Material	Machined steel
Weight	40 g (1.4 oz)
Installation Time	45 minutes with experience

Frequently asked questions

Is it compatible with S&W Model 686?: Yes, it is compatible with S&W K/L-frame revolvers like the Model 686, 586, and 19/66 series. Ensure your model uses a frame-mounted firing pin for proper fit. Installation requires removal of the factory hammer and stirrup.
Does it fit J-frame revolvers?: No, it does not fit J-frame or other small-frame revolvers. Designed specifically for S&W K and L frames only. Attempting installation on incompatible models may cause damage or unsafe operation.
How long does shipping take?: Shipping typically takes 3-5 business days within the continental U.S. via USPS Priority Mail. International orders may require 7-14 days depending on customs processing. Tracking is provided upon shipment confirmation.
Can I return it if it doesn't fit?: Returns are accepted within 30 days if the product is unused and in original packaging. Installation attempts void eligibility due to gunsmithing modifications. Contact support with your revolver model to confirm compatibility before purchase.

Sources & methodology. Editorial review and rating by Marcus Thorne based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-05-28.