Historical Background

The lineage of Windham Weaponry is deeply rooted in American firearm manufacturing heritage bringing together a veteran team of gunsmiths and craftsmen dedicated to producing duty-grade direct impingement firearms.

Within Windham Weaponry’s catalog, the SFS (Super Duty / Special Purpose) Series was developed as a modern, high-spec platform optimized for versatility, defensive application, and tactical adaptability across multiple calibers. Designed to meet severe duty requirements, the SFS line incorporates upgraded barrel steel, enhanced ergonomics, modular M-LOK handguards, and specialized finishes tailored for both standard rifle and compact pistol configurations.

Technical Overview

The Windham Weaponry SFS series utilizes a direct gas impingement operating system engineered across four major chambering profiles: .223 / 5.56mm NATO, .308 Win / 7.62×51mm NATO, 7.62×39mm, and .300 Blackout. Barrel offerings range from 9-inch medium profiles in compact pistol variants up to 18-inch profiles in precision rifle configurations.

Construction & Receivers

• Upper & Lower Receivers: Standard multi-caliber models utilize high-grade forged 7075 T6 aluminum receivers. The large-frame .308 platform features precision-machined 7075 T6 billet aluminum construction with fully ambidextrous operating controls, including an ambidextrous charging handle, bolt release, and magazine release.

• Barrels & Metallurgy: SFS barrels are crafted from 4150 Chrome-Moly Vanadium (CMV) steel (4150M on .308 models). Most variants feature chrome-lined bores and chambers for extreme durability under sustained fire, while specialized models utilize a corrosion-resistant Melonite QPQ finish. Twist rates are caliber-matched, ranging from 1:7 (RH) for heavy 5.56mm and .300 BLK projectiles to 1:10 (RH) for .308 Winchester.

• Bolt Assemblies: Critical components are machined from Carpenter 158 or 9310 alloy steel, with PVD protective coatings applied on heavy-caliber configurations.

Furniture & Ergonomics

• Handguards: Free-floating aluminum handguards (7-inch, 9.25-inch, 12-inch, or 15-inch options) featuring full-length top Picatinny rails and M-LOK attachment slots at key positions.

• Controls & Furniture: Standard equipment across the series includes B5 Systems Type 23 pistol grips, B5 Systems BRAVO collapsible stocks on rifle models, and 5-position SBA3 arm braces on pistol variants.

• Muzzle Devices: A2-style flash suppressors equipped across all standard chamberings.