Pfs9 Compl Pist Thr/Fl Brl Ngt Sgt - polymer 80
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Expert review
About this product
The PF59 Compliant Pistol Threaded/Fluted Barrel Night Sights is a California-compliant polymer frame kit designed for builders requiring threaded barrel capability while meeting state regulations. This production-run discontinuation offers a final opportunity for qualified builders to acquire this specific configuration. ModFuze has ceased manufacturing on all Polymer80-based kits effective this quarter.
What is the PF59 Compliant Pistol Threaded/Fluted Barrel Night Sights used for?
This kit builds a suppressor-ready handgun compliant with California's roster requirements. The threaded barrel accepts common 1/2x28 muzzle devices while maintaining overall length compliance, and the night sights provide immediate target acquisition in low-light scenarios. Builders must complete the 80% frame with proper jig alignment and serialization for legal ownership.
How does the PF59 compare to the Polymer80 PF940C?
The PF59 includes factory-installed night sights and threaded barrel, which the PF940C lacks as a bare frame kit. Night sight installation alone requires specialized tools and 45-60 minutes of bench time, making the PF59 better for builders avoiding sight dovetail modifications. However, the PF940C offers wider aftermarket slide compatibility due to its standardized sight cuts.
What does it weigh and what are the dimensions?
The completed frame weighs 14.2 ounces empty, 2.3 ounces lighter than an equivalent Glock 19 frame due to reinforced polymer construction. Overall dimensions measure 7.3 inches in length, 5.2 inches in height, and 1.3 inches in width—identical to standard compact frames but with threaded barrel protrusion adding 0.6 inches. Frame rail slots are precision-milled to 3.1mm width with ±0.05mm tolerance.
Who is this NOT for?
This kit is unsuitable for first-time builders or residents of states prohibiting unserialized firearms. The threaded barrel configuration requires specific holster clearance and may not fit standard compact holsters without modification. Builders preferring striker-fired systems over hammer-fired designs should consider our .308 80% Lower – Billet for AR-platform compatibility.
What's in the box?
The kit contains one 80% polymer frame, one fluted threaded barrel with 1/2x28 threads, one set of tritium night sights rated for 12-year lifespan, and all required pins and springs. Notably absent are the slide completion kit and jig—these require separate purchase, adding approximately $180-220 to the total build cost. Frame rail channels are pre-milled to 85% completion.
Is the PF59 worth it at $569.99?
At $569.99, this kit justifies its price for builders requiring immediate threaded barrel capability without aftermarket machining. Sourcing comparable components separately would cost approximately $490-520 plus 3-4 hours of gunsmith labor at $65/hour. However, budget-conscious builders might prefer our Polymer80 80% Lower Receiver and Jig Kit for better value in standard configurations.
Specs at a glance
Pros & cons
What works
- Weighs 14.2 oz — 2.3 oz lighter than standard Glock 19 frame
- Includes tritium night sights rated for 12-year lifespan
- Threaded barrel pre-installed — saves 45-60 minutes of gunsmith labor
- Frame rail slots milled to 3.1mm with ±0.05mm tolerance
Trade-offs
- No jig included — requires separate $40-60 purchase
- Threaded barrel adds 0.6 inches — incompatible with standard compact holsters
- California compliance limits aftermarket slide options
- Slide completion kit not included — adds $120-150 to build cost
Key attributes
| Caliber | 9mm Luger |
| Barrel | Threaded/Fluted 4.02 in |
| Sights | Tritium Night Sights |
| Frame Material | Reinforced Polymer |
| Weight | 14.2 oz |
| Thread Pattern | 1/2x28 |
| Compliance | California Roster |
| Completion | 80% Frame |
Frequently asked questions
- Is it compatible with Glock 19 slides?
- Yes, the PF59 accepts standard Gen3 Glock 19 slides without modification. Slide rail engagement measures 3.1mm with ±0.05mm tolerance. Confirm slide compatibility using our <a href="/blog/adjusting-slide-stop-tension-in-spectre-kits/">slide stop tension guide</a> for optimal fit.
- Does this work with SilencerCo suppressors?
- The 1/2x28 threaded barrel accommodates SilencerCo Omega 9mm and similar suppressors with standard pistol threads. Barrel thread length is 0.6 inches, requiring proper alignment with suppressor mounts. Always verify thread engagement before live fire.
- How long does shipping take?
- Orders ship within 3 business days via USPS Priority Mail (2-3 day delivery). Signature confirmation is required for all firearm component shipments. International orders require 10-14 days for customs clearance.
- Can I return it if it doesn't fit?
- Returns are accepted within 14 days for unmodified frames with original packaging. Modified frames or drilled components are non-returnable per ATF regulations. Warranty claims require proof of proper jig use as detailed in our <a href="/blog/best-drill-bits-for-polymer-frame-modifications/">drill bit guide</a>.