MSAR STG-556 Gen IV Bullpup – 5.56 NATO, final production with Picatinny rail & factory Waffle-Mag compatibility
Born from the legendary Steyr AUG lineage yet engineered and built in the USA, the MSAR STG-556 Gen IV delivers the compact handling of a bullpup with the modularity modern shooters expect. This late-run, hard-to-find Gen IV variant carries the desirable full-length Picatinny top rail, a tri-rail handguard, and true Steyr-pattern waffle magazine compatibility—making it a standout for collectors and practical users alike. A chrome-moly 16.5" barrel, a short-stroke gas piston system, and MSAR’s distinctive polymer furniture complete a package that balances performance, rarity, and iconic styling.
Condition
Rated Excellent overall. The matte-black polymer and anodized aluminum surfaces show only faint handling marks and a few superficial scratches. The bore is bright with a mirror finish and sharp lands and grooves, reflecting minimal round count. Mechanically tight, with clean internals and smooth, positive controls.
What’s Included
• Two 30-round MSAR waffle magazines (Steyr-pattern)
• Factory tri-rail handguard with quick-detach vertical fore-grip
• Installed 1/2x28 RH “tulip” AUG-style flash hider
• Right-hand bolt assembly
• Original MSAR STG-556 owner’s manual
Just a few details set this Gen IV apart. The receiver is machined from 7075-T6 aluminum and wears a Type III hard-coat anodize, while the polymer stock integrates sling-swivel sockets and a molded pistol grip for a 15" length of pull. The quick-change barrel system lets you remove or swap barrels in seconds without tools—handy for transport or future caliber conversions. A threaded muzzle, protected by the factory flash hider, welcomes suppressors or brakes. The twist-off ejection-port cover unique to Gen IV models, a short-stroke piston that keeps fouling out of the action, and the rock-solid cross-bolt safety round out the mechanical highlights.
Production of the STG-556 ended in 2015, and Gen IV rifles like this one were built only during 2008–2009. With factory parts and magazines increasingly scarce, clean examples have become harder to find. Whether you appreciate the bullpup’s compact 26-inch footprint, demand AUG ergonomics with U.S. parts count, or simply want a collectible slice of modern rifle history, this rifle covers all the bases.
If you have been waiting for a well-preserved, late-generation STG-556 to complete your collection—or to put into immediate service—this example is ready to impress.