The Retro-Arms Upper delivers rugged performance with a heavy A4 barrel (.750 FSP build) for sustained fire capability. Outfitted with a Light Support Weapon (LSW) handguard and a TRI-AD rail on the front sight post, this upper provides a stable, modular platform for mounting accessories. Designed for durability and reliability, it offers enhanced heat management and versatility for mission-ready applications. FeaturesHeavy A4 Barrel Upper for solid strength and long-lasting accuracy.Withstands high-round-count training without performance loss.0.750" FSP Build Upper adds rigidity and stability for rapid fire.Perfect for drills, repeat fire, and consistent shooting.