Tracer ammunition

More often, however, the entire magazine was loaded four-to-one, on both fixed offensive and flexible defensive guns, to help mitigate the difficulties of aerial gunnery.

The United States relied heavily on tracer ammunition for the defensive Browning M2 .50 caliber machine guns on its heavy bombers such as the B-24 Liberator.

There are fireworks manuals from the 14th century specifying a way to make "flaming cannonballs," with pitch, gunpowder, a cloth/cordage cover, and finally smearing them with lard and tallow.

However, these were not always visible, especially as the effective range of ammunition increased dramatically during the later half of the 19th century, meaning the bullets could impact a mile or more away in long-range area fire.

In the early 20th century, ammunition designers developed "spotlight" bullets, which would create a flash or smoke puff on impact to increase their visibility.

Normal bullets merely had the effect of causing a slow leak, but tracers could ignite the hydrogen gasbags, and bring down the airship quickly.

In World War II US Naval and marine aircrew were issued tracer rounds with their side arms for emergency signaling use as well as defense.

The color-emitting atom in the salt is also released and reacts chemically with excess oxygen providing the source of the colored flame.

Therefore, in the case of using strontium nitrate and magnesium, to produce a red-colored flame that is not over-powered by the white light from the burning fuel, a chlorine donor is provided in the pyrotechnic mixture, so that strontium chloride can also form in the flame, cooling it so that the white light of MgO is greatly reduced.

Trajectory match, or ballistic match, is achieved between two bullets of slightly different weight and aerodynamic characteristics by adjusting the cartridge propellant weight, propellant type, and muzzle velocity, to remain within safe pressure limits, yet provide each bullet with a trajectory to the target that is nearly identical over all atmospheric conditions and target engagement ranges, while using the same gunsight aimpoint.

Trajectory match is not intended to be perfect, an engineering impossibility under the closest of similarities between the two bullets, that is further complicated in the case of the tracer losing mass and changing its drag properties as it flies.

To make it more difficult for an enemy to do this, most modern tracers have a delay element, which results in the trace becoming visible some distance from the muzzle.

[10] The forward portion of a tracer bullet contains a substantial slug of lead filler, nearly as much as the non-tracer ball round that it trajectory matches.

Nevertheless, under some circumstances, a slight degradation in lethality can often be made up for by the psychological and suppressive-fire effects tracer bullets can have on an enemy who is receiving them.

Modern jet fighters primarily rely on radar and infrared seeker missiles to track and destroy enemy planes and laser-guided missiles to attack surface targets, rather than the plane's cannon, which may be just an ancillary weapon for air-to-air combat; although in the ground attack role, cannon fire may be emphasized.

However, modern fighter aircraft use gyroscopes and inertial sensors coupled with radar and optical computing gunsights that make the use of tracers in cannon ammunition unnecessary.

Thus one of the primary reasons for using tracers on aircraft in the first place, uncertainty over where the bullets will end up in relation to the target, is removed.

[14] During spells of hot weather, the Ministry of Defence will suspend the use of tracers for non-essential training to reduce the risk of wildfires on sites such as Salisbury Plain.

[15] On February 24, 2013, a fire was started at DFW Gun Club in Dallas, Texas, by the use of a tracer round inside the facility.

The two individuals who were deemed responsible for the fire were shooting the tracer round ammunition outside of the designated target area at the gun range.