Full metal jacket bullet

For the Stanley Kubrick film, see Full Metal Jacket.

An example of FMJ bullets in their usual shapes: pointed ("spitzer") for the 7.62x39mm rifle and round-nosed for the 7.62x25mm pistol cartridges.

A full metal jacket (or FMJ) is a bullet consisting of a soft core (usually made of lead) encased in a shell of harder metal, such as gilding metal, cupronickel or less commonly a steel alloy. This shell can extend around all of the bullet (alternatively termed a total metal jacket round) or, more often, just around the front and sides with the rear lead part left exposed. The jacket allows for higher muzzle velocities than bare lead without depositing significant amounts of metal in the bore. It also prevents damage to bores from steel or armor-piercing core materials. The appearance of FMJ ammunition is highly distinctive when compared to hollow-point or soft point bullets. Historically, the first successful full metal jacket rifle bullets were invented by Lt. Col. Eduard Rubin of the Swiss Army in 1882. Full metal jacket bullets were first used as standard ammunition in 1886, for the French Mle 1886 Lebel rifle.^{[citation needed]}

Disadvantages

There are some disadvantages to jacketing a bullet. For instance, full metal jacket bullets have different properties, both in terms of behavior inside the barrel of the gun and also in flight. Whereas hollow point and soft-tipped bullets are designed to expand upon impact, full metal jacket bullets are limited in their capacity to expand. This makes the bullet pierce through, in most cases leading to smaller wound size. Hollow point and soft tipped bullets are for use against soft targets only, such as animals or people, whereas full metal jacketed bullets can be indiscriminately used against soft and hard targets.

FMJ with variable cores

Some designs of FMJ rifle ammunition inflict more destructive gunshot wounds than others. Not all FMJ bullets contain a simple lead filling. Here are some examples:

Although British Mark 7 .303 ammunition is compliant with the terms of the Hague Convention, it creates more destructive gunshot wounds than standard spitzer bullets due to its internal design. The center of gravity of the Mark 7 bullet is deliberately shifted towards the rear. This is achieved by constructing the front third of the interior of the bullet from a lighter material such as aluminum or wood pulp. The result is a tail-heavy FMJ bullet which yaws violently after hitting the target. The .303 British Mark 7 ammunition has been replaced by the 7.62x51mm NATO. Most 5.45x39mm FMJ ammunition is made with an air space in the tip of the round similarly shifting the weight to the rear causing immediate and violent tumbling when it contacts a soft target. 5.56x45 ammunition traveling at the proper velocity will also tumble and the round will break apart at the cannelure and fragment.

Images of FMJ ammunition

.25 ACP

.32 ACP

7.62×25mm Tokarev

.32 ACP, 7.62×25mm Tokarev, 9×19mm Parabellum

7.65×22mm Parabellum

.38 S&W

.380 ACP

9×18mm Makarov

.38 Super

.40 S&W

.45 ACP

Yugo 7.62x39 M67.jpg

7.62×39mm

7.62×39mm

7.62×39mm

5.56×45mm NATO

.303 British

.280 Ross & .303 British

7.92×57mm Mauser from World War I

Steel-cased German 7.92x57mm Mauser manufactured in 1941

7.92×57mm Mauser dated 1941

7.92×33mm Kurz

7.5×55mm Swiss

Three recovered 7.62×51mm NATO FMJ bullets (next to an unfired cartridge), showing rifling marks

7.62x54mm

From left to right: 7.62x54mm, 7.62×39mm and 7.62×25mm

See also

• Soft-point bullet
• Hollow-point bullet

References

• Huon, Jean (1988). Military Rifle and Machine Gun Cartridges. Alexandria, Va.: Ironside International. ISBN 0-935554-05-X. OCLC 24498827. 

External links

• Declaration (IV, 3) concerning Expanding Bullets, made at the 1899 International Peace Conference at The Hague, which entered into force on September 4, 1900
• European Ammunition Box Translations
• Photos showing terminal effects of British Mark 7 .303 bullets