Winchester 1964 SPIW: Flechettes and a Blow-Forward Grenade Launcher
This video examines the Winchester 1964 SPIW (Special Purpose Infantry Weapon) entry into a US Army trials program aimed at enhancing small arms lethality through hyper-velocity flechettes and integrated grenade launchers. The featured rifle boasts a 60-round drum magazine for flechette rounds and a muzzle-mounted, blow-forward 40mm grenade launcher. Challenges in development, particularly with the flechette cartridge's sabot, are discussed. Despite its innovative concepts, the Winchester design proved unsuccessful due to poor balance, handling, and reliability issues during firing trials. The video thanks the Rock Island Arsenal Museum for access.














