Three different types of explosive and incendiary small-arms ammunition have been captured from the Japanese in the Southwest Pacific area. Because of the unusual characteristics of this ammunition, serious injuries sometimes have resulted when soldiers have tampered with it out of ignorance or curiosity.

Apparently first manufactured for use in Japanese aircraft or antiaircraft weapons, some of this ammunition has been found loaded in five round clips, presumably for use in infantry weapons. This ammunition—7.7-mm or 7.92-mm—may easily be recognized by color markings at the junction of the bullet with the cartridge or around the primer cap. It should not be handled carelessly.

Japanese Army Incendiary Bullet

Japanese Army Explosive Bullet

The three different types of ammunition are the 7.7-mm rimmed Navy round, the 7.7-mm semi-rimmed Army round, and the 7.92-mm rimless Army round.

Explosive and incendiary rounds may be recognized by the color marking as indicated in the following table:

The 7.7-mm rimmed Navy round is of two kinds—one is a combination high-explosive and incendiary, the other only incendiary. Both types of the Army ammunition—the semi-rimmed and the rimless—are loaded either with an incendiary bullet or with a strictly explosive bullet (see illustration on page 32).

These bullets are not fuzed, but explode or ignite when the copper jacket is ruptured on impact with the target. The explosive bullet may be recognized by its flat nose, but the incendiary has the pointed nose of an ordinary bullet. The explosive bullet is capable of blowing a 3-inch hole in a sheet of aircraft Duralumin.