FN SCAR | F5-MFG GEN 3 F5-ACR Cyberarm Light Brace System
F5 Mfg Cyberarm Light Brace — Hosted by the F5 Mfg F5-ACR Gen 3 Chassis
Ultra-Lightweight Pistol Stabilizing Brace — 95.75 Grams
The FN SCAR was built bufferless from the ground up, with its recoil system housed entirely in the upper receiver. That makes it a natural host for the F5-ACR Gen 3 Chassis. Bolting directly to the SCAR’s rear stock interface, this configuration keeps the platform’s fire-while-folded capability intact while cutting rearward weight to a minimum.
The Cyberarm Light variant weighs in at 95.75 grams — roughly half the 179.50-gram standard version — shifting balance forward and taking mass off the tail of the gun where you feel it most.
Each chassis is CNC-machined in-house by F5 Mfg from solid 6061 billet. The skeletonized profile is the result of material-optimized modeling: metal is removed only where the load path allows it, so the finished part stays among the most rigid components on the rifle. On 7.62 SCAR builds, that rigidity matters — there’s no flex or rattle under recoil, and zero return is repeatable through the fold cycle.
Topside, the Gen 3 chassis carries a tool-less adjustable cheek riser. Given the SCAR’s high rail line and the tall optic mounts many shooters run on it, that adjustment range solves a real ergonomic problem rather than adding a spec-sheet bullet. The side-folding mechanism locks up positively in both positions.
This is a pistol stabilizing brace — not a rifle stock. It retains the standard Cyberarm brace attachment for arm support in pistol-configured builds while keeping the footprint short and foldable.
Key Features
- Pistol stabilizing brace — not a rifle stock
- 95.75 grams for reduced rearward mass and faster handling
- Direct fit to the FN SCAR rear stock interface — no buffer tube, no adapter block
- Tool-less adjustable cheek riser for optic and head-position alignment
- Side-folding with positive lockup; preserves fire-while-folded
- CNC-machined 6061 billet with load-path skeletonization
- Cyberarm brace attachment for secure, ergonomic stabilization
- Made in the USA
Why It Matters on a SCAR
The SCAR’s factory stock is capable but heavy, and its rear-biased mass is the first thing most owners want to address. The F5-ACR Gen 3 Chassis with the Cyberarm Light Brace removes that weight without giving up folding function or lockup rigidity — a meaningful upgrade for short-barreled and PDW-style SCAR builds where every ounce behind the receiver works against you.
Building the Host Gun
This chassis fits both sides of the SCAR line — the 5.56/300 BLK guns and the 7.62 rifles — so the build path depends on what you’re after.
For compact pistol builds, the 7.5-inch SCAR 15P is the shortest way in. It ships at 5.65 lbs with a 19.75-inch overall length, and gets shorter still once the Cyberarm Light Brace is folded. Palmetto State Armory currently has both variants well under FN’s list:
- FN SCAR 15P — 5.56 NATO, 7.5″ barrel, 30rd, FDE — $1,999.99 (reg. $3,738.99). Chrome-lined barrel, three-prong flash hider, FDE anodized receiver, fully ambidextrous controls. Pair it with the FDE or OD Green chassis for a matched build.
- FN SCAR 15P — 300 Blackout, 7.5″ barrel, 30+1, Black — $1,999.99 (reg. $3,820.99). Modeled after the SCAR-SC PDW, with an adjustable low-flash gas regulator and a bolt carrier tuned for the pistol-length gas system. The natural choice for a suppressed subsonic setup, where trimming rearward weight matters most.
For 7.62 builds, the FN SCAR 17S in 7.62x51mm NATO is where this chassis earns its keep. The factory 17S stock is a telescoping side-folder in composite polymer, and it’s the heaviest single thing hanging off the back of the gun — an 8-lb rifle carries a lot of that mass behind the receiver. Swapping to the F5-ACR Gen 3 Chassis pulls weight forward and stiffens the rear interface, which is exactly what a hard-recoiling .308 wants. The chassis’s billet lockup doesn’t develop the play a polymer folder eventually does.
Every SCAR in the line runs FN’s short-stroke gas piston system with no buffer tube, so the chassis drops straight in across calibers with no adapter hardware.
Important Compliance Notice
This product is a pistol stabilizing brace, not a rifle stock. Verify that your firearm configuration complies with all applicable federal, state, and local regulations.
