Page "M252 mortar" Paragraph 20

The range of a mortar is controlled by what are referred to as " charges.

" Charges are semi-circular nitrocellulose donuts that resemble a puffy letter " C ." Ammunition for the M252 mortar come with four charges.

Longer range shots require more propellant than can be easily stored in the tail of the round, hence the necessity of the charges to be placed on the round.

Once a target is ranged, the correct charge is placed on the round by removing the charges from the projectile.

Once the charges are verified by the section leader, the round is dropped down the muzzle of the tube.

The round, pulled by gravity, accelerates down the smooth bore of the mortar until the primer ( in the base of the tail boom of the round ) strikes the firing pin located in the bottom of the mortar tube.

The primer detonates igniting the charge in the tail fin which in turn ignites any of the C-charges on the round.

The expanding gas created by the burning charges push against the obturator band on the round, sealing the gasses and gives the round forward momentum.

The round is accelerated by the gasses until it leaves the end of the tube.