Pictured above, on right side: Left is XM156Right is M48A1, also the tank is shooting a Shillelagh 152 mm anti-tank guided missile.
One Cartridge, not a box: .50 Cal Spotter-Tracer, XM156 (Commercial version) produced with older 50 BMG brass cases by pulling bullets older .50 Cal. BMG cases and replacing them with the M48A1 projectiles. Cartridges will have mixed Head-Stamps.
History of the XM156 Spotter Tracer Cartridge:
The original XM156 cartridges were an experimental long range spotting cartridge used in the XM121 machine gun, to range the distance for the Shillelagh 152 mm anti-tank guided missile (pictured) before firing the missile.
The original XM156 cartridges were produced by (or) for the military by using .50 caliber BMG cases with a “FA 60” head-stamp with slightly different dimensions than the standard .50 Cal. BMG case and loaded d with the M48A1 projectile.
The M48A1 projectiles have primer at the tip to ignite a mixture that produces a smoke spotter on impact, and also a tracer cup in the rear of the projectile to produce a tracer out to 1500 yards.
