The term 'AMMO UNIT' can be broken down into two crossword solutions: 'BULLET' (6 letters) and 'ROUND' (5 letters). A BULLET is a type of ammunition used in firearms, typically consisting of a metal or lead projectile encased in a copper jacket. A ROUND is a single unit of ammunition, usually consisting of a cartridge containing a projectile, propellant, primer, and casing. Both bullets and rounds are essential components of an ammo unit, which is a unit of ammunition used in firearms.