Ordnance Ammunition
Modern artillery ordnance ammunition is generally of two types: separate loading and semi-fixed. Semi-fixed ammunition (rounds) appear in the form of a projectile mated with a cartridge case which contains the propellant and they resemble small arms rounds.
The canister is outfitted with a primer on its base which fires upon contact from the firing pin. Gunpowder, precision machined to burn evenly, is contained inside of cloth bags that are numbered. US/NATO 105 mm howitzers use semi-fixed ammunition, containing seven powder bags referred to as increments or charges. Putting the powder in bags allows the howitzer crew to remove the increments when firing at closer targets. The unused increments are disposed of by analysing burning in a powder pit at a safe distance from the guns.
Above a certain size, semi-fixed rounds are impracticable; the weight of the whole assembly is too much to be carried effectively. In this case separate loading ammunition is used: the projectile and propelling charge are supplied and loaded separately. The projectile is rammed home in the chamber, the powder charge(s) are loaded (usually by hand), then the breech is closed and the primer is inserted into the primer holder on the back the breech. Separate loading ammunition is typically used on 155 mm and larger howitzers. Several propellant types are available for 155 mm howitzer.
All normal projectiles arrive at the weapon with a plug in the fuze well on the nose of the projectile. Using a special fuze wrench, the plug is unscrewed and a fuze is screwed in. The decision as to which type of fuze to use is made by the fire direction center and carried out by the gun crew.
The armaments fitted to early tanks were contemporary field or naval artillery pieces and used the same ammunition. When tank versus tank combat became more important, and specific tank guns did not exist, it became common to adapt anti-aircraft guns (artillery) which fired shells of high velocity, which were needed for high altitude targets. As the armour applied to tanks increased, ammunition for tank use paralleled that of anti-tank guns. Current tank gun ammunition is a single fixed round ("shell" and charge combined in a single piece) for quick loading, the propellant is in a combustible case, thus negating empty shell casings. The primary anti-armor (anti-tank) warhead is the sabot round, a shaped charge or sensor fuzed warhead.
The tank made horse cavalry obsolete, and while an infantryman could deal with a horse-mounted enemy, new weapons were needed to defeat a tank or other armored fighting vehicle. The first anti-tank weapons given to the infantrymen were based upon small arms; for example the anti-tank rifle. As even the later designs of tanks carried more armour, the limit of a man-portable rifle that could fire a round with sufficient kinetic energy to penetrate the armour was reached.
The introduction of the shaped charge warhead gave the infantryman a weapon that used chemical energy rather than kinetic to penetrate armour in a focused manner, which made them more effective than large grenades. When propelled by a rocket, the shaped charge gained range as well. Weapons such as the US Bazooka and German Panzerfaust, although bulky, were suitable for infantry use—though they were designed to be short ranged weapons, which simplified accuracy for striking a vehicle's weak points.
After World War 2, the advent of the missile delivered both great range and accuracy and provided infantry with a weapon that could reliably destroy the heaviest tanks at long distances.
Today's infantryman can deploy sophisticated multi-spectral man-portable surface-to-air missiles equipped with the ability to reject decoys and defeat counter-measures.
Since aircraft are relatively light in weight, and delicate in construction, this, combined with their highly flammable fuel, made aircraft more susceptible to fatal damage since their first mass usage in World War I; sometimes being brought down by single bullet, when striking something vital in the airplane. The main weaknesses of ammunition provided to infantry to deal with aircraft were limited range and small warheads; both due to the necessity of maintaining man-portable weapons.
An example of a modern surface to air missile for infantry is the FIM-92 Stinger MANPADS (Man Portable Air Defence System), provided as an all-up round in a canister it is attached to a launcher unit and is ready to expend. Numerous other missiles in this class exist from different nations of origin. Infantry machine guns and rifles may improve their ability against aircraft by utilising tracer ammunition, to allow the aimer to better gauge the lead aim necessary to strike his target.
Weapons developed primarily for anti-tank roles can add proximity fusing to increase the probability of a kill by having the warhead detonate nearby the target without having to make contact.
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