Foxtrot Mike Products has launched the ISU-556-G2, an advanced bufferless, integrally suppressed 5.56 upper receiver. Featuring a monolithic billet design, integrated recoil system, and compatibility with modern stock systems, it offers enhanced performance and minimal recoil. The system is optimized for reliability and accuracy, requiring only one tax stamp for legal use.
Foxtrot Mike Products state “The ISU-556-G2 is the most advanced AR-pattern upper Foxtrot Mike Products has ever produced. Built on our extremely popular Gen 2 bufferless platform, the ISU-556-G2 takes everything that made the ISU-556 exceptional—and elevates it with a monolithic billet receiver, integrated recoil system, and folding-stock compatibility. This is a purpose-built, integrally suppressed 5.56 system designed for shooters who demand maximum performance, minimal recoil, and modern configurability—without compromise.
Gen 2 Monolithic Architecture
The ISU-556-G2 is built around a monolith-style billet upper receiver, precision-machined
from premium aluminum and engineered for extreme rigidity.
● Interlocking upper and handguard interface eliminates deflection and movement
● Thermally fit barrel-to-upper interface for unmatched consistency and durability
● Enhanced alignment and repeatability under sustained fire
The result is a rock-solid suppressed platform that maintains zero, resists heat-induced shift,
and stands up to hard use.
Bufferless by Design
Unlike traditional AR systems, the ISU-556-G2 features an integrated recoil spring system housed entirely within the upper receiver.
What that means:
● No buffer tube required
● Fires reliably from the folded position
● Compatible with modern folding and bufferless stock systems
Using the included Picatinny rail adapter, users can mount the ISU-556-G2 to any mil-spec AR-15 lower receiver, unlocking a wide range of modern stock and brace options common to today’s bufferless rifle platforms
Suppressor-First Gas System — Refined Further
Like the ISU-556, the G2 uses FM Products’ one-piece barrel integrating the barrel, gas block, and barrel extension into a single precision component. The system retains:
● AR-10-sized, thermally fit barrel extension
● AR-10-sized bolt head
● Extreme strength well beyond standard AR-15 designs
The 16.2″ barrel is tuned to replicate the dwell time of a 10.5″ carbine, while the final 5.7 inches of barrel—inside the suppressor—feature over 100 gas ports intersecting the lands of the rifling. The modular gas port, sized .015″ smaller than a standard 10.5″ carbine, dramatically reduces back pressure, recoil impulse, and system wear—especially critical in a lightweight, bufferless platform. Paired with the reduced reciprocating mass of the Gen 2 operating system, the ISU-556-G2 delivers an even flatter, softer shooting experience than the original ISU-556.
Flow-Through Integral Suppression
The ISU-556-G2 uses the same low-back-pressure, flow-through suppressor architecture,
optimized for 5.56 performance:
● 1.5″ seamless 316 stainless steel outer tube
● High-temperature silicone wrap for heat mitigation
● Precision-machined 17-4 stainless baffles
● Conical 17-7 high-temperature spring for alignment, preload, and gas cooling
● Labyrinth seals at the barrel and end caps to prevent gas leakage
Gases are routed through a complex internal pathway—expanding, cooling, and venting through metered exhaust ports—producing excellent suppression while minimizing system pressure. Because the baffles are installed around the one-piece barrel, baffle strikes are mechanically impossible.
Accuracy Through Engineering
FM Products again intersects gas ports with the lands of the rifling, not the grooves—a monumental manufacturing challenge that preserves projectile stability while venting gas. With muzzle velocities exceeding 2,700 FPS, the ISU-556-G2 offers suppressed performance without sacrificing accuracy or terminal capability
Configured for Modern Use
● Monolithic billet Gen 2 upper receiver
● Integrated recoil spring system
● Fires folded
● Standard mil-spec AR-15 bolt carrier
● 8.5″ M-LOK® handguard, accessory mounting on 7 sides
● Compatible with any mil-spec AR-15 lower
● Designed to run reliably with Super Safeties and FRTs
One Stamp. Full Capability.
With an overall barrel length of 16.2 inches, the ISU-556-G2 requires only one tax stamp for the integrally suppressed configuration—no SBR paperwork required.
LEARN MORE: https://fm-products.com/