"Highly flammable buckshot rounds consisting of a thermite/phosphorous mixture; rounds cause catastrophic physical damage to enemy combatants."
―W-Y ID16 Incendiary Shell description (from Aliens: Colonial Marines)

The W-Y ID16 Incendiary Shell is highly flammable buckshot round consisting of a thermite/phosphorous mixture manufactured by Armat Battlefield Systems for use with an underbarrel shotgun attachment for the MK221 Tactical Shotgun.


  • The ID16 Incendiary Shell launcher in Aliens: Colonial Marines is visually identical to the U7 Tac-Shotgun.
  • The concept of attaching a shotgun to a shotgun seems entirely redundant, as it would surely be possible to make incendiary shotgun cartridges that would fit in the MK221 without the need for an additional attachment, thus saving a large amount of weight on the weapon overall. The only conceivable benefit is the ability to have both types of ammunition chambered and ready to fire at the same time, but with a magazine attachment it would be possible to switch between ammo types rapidly anyway.