FMJ - Full Metal Jacket. A bullet completely enclosed (except for the base) in a hard metal jacket (usually an alloy of copper, sometimes mild-steel). This is the only type of bullet permitted in warfare.

JFP - Jacketed Flat Point. Same as the FMJ, however instead of the tip of the bullet being rounded, it ends in a flat plate.

JHP - Jacketed Hollow Point. A bullet constructed of a soft lead core enclosed in a hard metal jacket. The top of the bullet has an opening in the jacket, exposing a hollow lead core. On the force of impact, the bullet is forced to open up and expand, resulting in less penetration but greater damage due to the larger diameter of the now expanded bullet.

JPF - Jacketed Pre-Fragmented. The bullet consists of a metal jacket as in the JHP, but instead of the core being solid lead, it consists of a number of separate projectiles, such as lead shot (the most common), metal disks, or polymer, (or any combination) compressed into the jacket. The tip of the bullet usually has a polymer "cap" with a round-nose profile to ensure reliable feeding. JPF bullets are usually much lighter than normal bullets, and travel at extreme velocities.

JTC - Jacketed Truncated Cone. Very similar to the JFP, but the sides of the bullet are straight and end in a flat plate, as opposed to the JFP where the sides are more rounded. The JTC bullet has the profile of a cone with a flat plate at the tip instead of a point.

LTC - Lead Truncated Cone. Same as JTC, however the bullet is constructed completely of lead and has no metal jacket.

LHP - Lead Hollow Point. Same as the JHP, but the bullet is constructed completely of lead and has no jacket.

LRN - Lead Round Nose. Same as the FMJ, however the bullet is constructed completely of lead, and has no metal jacket.

PHP - Plated Hollow Point. Same as the JHP, however, instead of the lead core being enclosed by a metal jacket, it is instead coated with a thin layer of chemically deposited metal.

SJHP - Semi-Jacketed Hollow Point. Same as the JHP, except the jacket does not completely cover the lead core. Usually a small section (about 2mm or 1/8") at the top of the bullet is left exposed. This is an older design, but is still common in the .38 special, .357 Magnum and .44 Magnum calibers.

SWC - Semi Wad Cutter. Very similar to the LTC, however the base of the bullet has a slight ridge or shoulder. Thus the diameter of the base of the cone is slightly smaller than the base of the bullet itself. This causes the bullet to cut neat round holes in paper targets, instead of ripping the paper.

TMJ - Total Metal Jacket. Same as the FMJ, however, unlike the FMJ where the metal jacket encloses the whole bullet except the base, the TMJ bullet's base is also enclosed by the jacket.

See the "Glossary of Gun Terminology" for additional information.