$ 24.75 per
Colt ~ Winchester
5.56x45mm DUPLEX
Phase (3) DAAA21-86-0367
In the late 1980s Colt & Winchester
submitted a few different experimental
"Duplex" (2 projectiles to the cartridge,
one behind the other) to the US Military
Trials. These are one type for those
"Phase III" experimental trial tests.
The idea of the duplex cartridge loading
is to launch two projectiles per firing to
increase the odds of hitting the target
(and/or) two holes in the enemy is
better than one.
I believe they would of had problems
keeping the second projectile in place
inside the case without the extended
neck version and the  idea never really
caught on; (to my  limited knowledge)
the U.S. Military does not use or have
any duplex cartridges in  their arsenal.
Head Stamped WCC 88 for
Winchester, 1988
Out of  Stock