Firepower versus precision fire
Rifles are good at giving accurate single shot fire at point targets. Ammunition consumption is reduced to a minimum, and when firing at visible targets at short to medium ranges the hit probability per shot can be high. However, although they are capable of full auto fire, assault rifles are not good at doing the work of a machine gun. A three second burst will empty the magazine. The user will soon fire his entire basic load. The weapon will overheat, risking damage to the weapon and unintended firing due to cook-offs. It is difficult to control the weapon, so hit probability will be very low except at very short range.
Designed specifically for full automatic sustained fire the machine gun will provide firepower much more effectively and reliably. For suppressive fire, to cover an area, against groups of infantry who are moving, and/or difficult to see, the machine gun will be far more effective.
Most rifles and light machine guns fire intermediate calibre cartridges such as 5.56mm. These cartridges are most effective at less than 500m. This is even more true as the “standard” barrel length has been shortened (for example from 20″ barrels on the M16 to 14.5″on the M4). A precision rifle/designated marksman rifle firing a more powerful cartridge such as 7.62mm NATO from a longer barrel allows the bullet to reach higher velocity giving a flatter trajectory and more impact energy on target, which is most useful at longer range. Generally fitted with a higher magnification optical sight this type of weapon is very effective at identifying and engaging high value targets (command personnel, radio operators, heavy weapons crews).
Moving through buildings or jungle engagements will often be sudden, at short range, and from almost any direction. A smaller, lighter weapon will be easier to use, and their limited range will not be a concern. Short barrelled rifles are useful as “entry weapons” in buildings.
Type of effect and trajectory
Rifles and machine guns fire kinetic energy munitions with a flat trajectory. They must achieve a direct hit, and engage targets in direct line of sight (except for highly specialized use of medium and heavy machine guns). Enemy personnel behind a wall, in a ditch or depression, or behind a berm are protected.
Grenade launchers fire explosive munitions with a curved trajectory, so grenades can be fired into areas that cannot be covered by rifles and machine guns. The grenade does not need to achieve a direct hit, the fragments will cause casualties around the point of impact. A grenade fired through a window can incapacitate personnel who are not in line of sight, and are protected from bullets.
Grenade launchers can also fire illumination and smoke grenades which can be very useful in certain situations.
Many users carry a handgun as a secondary weapon. This provides an emergency solution if the primary weapon cannot be used. Reloading or clearing a stoppage with the primary weapon may take too long when in very close proximity to the enemy. Damage to the weapon, or injury may make it impossible to use the primary weapon.
FN Herstal offers a full range of weapons that can fully equip an infantry unit. Assault rifles in different lengths and calibres, precision rifles, ultralight, light, medium and heavy machine guns in different calibres, stand-alone or underslung grenade launchers, and handguns. There is also a range of munitions for these weapons.