Made by the Royal Navy at HMS Excellent, the RN’s gunnery school, TRACER OBSERVATION shows the use of tracer ammunition in combat conditions against aircraft. Using animation and live action, the film shows how tracer works, and how it can be used to adjust shell trajectories against a moving target. The film also contains a fascinating look at some of the optical effects produced by the human eye when dealing with a fast moving target such as an aircraft. A typically British film, at 8:11 it uses a bottle of Guinness Stout to make some points about elevation relative to the position of a distant target.
Tracer ammunition (tracers) are bullets or cannon caliber projectiles that are built with a small pyrotechnic charge in their base. Ignited by the burning powder, the pyrotechnic composition burns very brightly, making the projectile trajectory visible to the naked eye during daylight, and very bright during nighttime firing. This enables the shooter to make aiming corrections without observing the impact of the rounds fired and without using the sights of the weapon.
When used, tracers are usually loaded as every fifth round in machine gun belts, referred to as four-to-one tracer. Platoon and squad leaders will load some tracer rounds in their magazine or even use solely tracers to mark targets for their soldiers to fire on. Tracers are also sometimes placed two or three rounds from the bottom of magazines to alert the shooter that his weapon is almost empty. During World War II, aircraft with fixed machine guns or cannons mounted would sometimes have a series of tracer rounds added near the end of the ammunition belts, to alert the pilot that he was almost out of 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. Tracers were very common on most WWII aircraft, with the exception of night fighters, which needed to be able to attack and shoot down the enemy before they realized they were under attack, and without betraying its own location to the enemy defensive gunners.
Before the development of tracers, gunners relied on seeing their bullet impacts to adjust their aim. 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. However, these projectiles were deemed in violation of the Hague Conventions’ prohibition of “exploding bullets.” This strategy was also useless when firing at aircraft, as there was nothing for the projectiles to impact on if they missed the target. Designers also developed bullets that would trail white smoke. However, these designs required an excessive amount of mass loss to generate a satisfactory trail. The loss of mass en route to the target severely affected the bullet’s ballistics.
The United Kingdom was the first to develop and introduce a tracer round, a version of the .303 cartridge in 1915. The United States introduced a .30-06 tracer in 1917. Prior to adopting red (and later, other color) bullet tips for tracers, American tracers were identified by blackened cartridge cases.
HMS Excellent is a Royal Navy “stone frigate” (shore establishment) sited on Whale Island near Portsmouth in Hampshire. HMS Excellent is itself part of the Maritime Warfare School, with a Headquarters at HMS Collingwood, although a number of lodger units are resident within the site, the principal of which is the Headquarters of Commander in Chief Fleet (Navy Command Headquarters).
This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD, 2k and 4k. For more information visit http://www.PeriscopeFilm.com
