XM-148: Colt's Vietnam Grenade Launcher
The Colt XM-148 was the US military's first under-barrel grenade launcher, developed from the SPIW program for the M16 rifle. Despite its innovative design, it suffered from significant flaws, including a snagging trigger bar, high cocking force, and mechanical complexity. These issues led to its replacement by the simpler and more reliable M203, making the XM-148 a notable but ultimately unsuccessful footnote in firearms history.









