There are a lot of buzzwords about rounds that get passed around. For a new or casual gun owner, these can cause some confusion. As I sat down to write this, I made a list of bullet terms, and the list just seemed to go on and on. I will keep this list more basic and give descriptions of terms that most shooters are likely to see.
FMJ is an acronym for “full metal jacket.” This term was popularized by the Stanley Kubrick film of the same name. It refers to the copper or steel jacket around the bullet itself. FMJs are usually the cheapest rounds and most often used for plinking. These rounds are a poor choice for self-defense, since they need to over-penetrate the attacker. The Geneva Convention forbids usage of any rounds besides FMJs for war. So when the term “surplus of military spec” is used, you can assume it is a full metal jacket round.
“Jacketed hollow point” is a term used for rounds meant to expand on impact, preventing over-penetration and an increased wound channel. The bullet has a hollow cavity in the center. The rest of the bullet is jacketed by copper. These rounds are the preferred rounds to be used for self-defense. You may also see the acronym BJHP which simply stands for “brass jacketed hollow point.”
Soft point rounds are a jacketed round with a small portion at the center without a copper jacket. These leave the softer lead exposed, increasing expansion and lowering penetration. For defensive use these rounds have fallen out of favor and have been replaced with JHPs. The rounds are still occasionally used as hunting rifle bullets. May also be known as “soft tip.”
A wad cutter is a flat front bullet that is flush with the rounds case and was designed to shoot paper targets. This round fires at a subsonic velocity and has minimal recoil. The purpose of the flat front is to punch nice, neat little holes in paper to make scoring easier. Seen most often in 38 special, the round is a favorite for competition.
Semi wad cutters are used in both automatics and revolvers. Most automatics have trouble feeding wad cutters reliably, so the SWC was invented. The SWC still pokes nice neat holes in paper. The SWC is not flush with the case of the round and has a slight narrowing point with a flat face. The NRA conducted tests, and round regular wad cutters were more accurate than semi wad cutters for competitions.
The word magnum was first used to describe larger than average champagne bottles. The term “magnum” was first applied to the .357 magnum round. The .357 was derived from the 38 special, the difference between them being a heavy increase in power and case size. A magnum is a word used to describe powerful rounds, but is not a catch-all for powerful rounds. The term magnum is applied when the ammunition inventor names the round. This tern is most often used to compare the magnum round to an original lower-powered and shorter cased round. Examples are the .38 special to .357 magnum, and the .44 special to the .44 magnum.
A wildcat cartridge is a round designed for an uncommon firearm or caliber. A wildcat is typically an improved version of a previous round. Usually very expensive and hard to find commercially, so they must be hand-loaded by enthusiasts.
+P and +P+
A +P or +P+ (or occasionally called “over-pressure ammunition”) is ammo loaded to a higher pressure than normal rounds. This is done to improve the round’s defensive performance by squeezing as much power as they can, while remaining safe. These rounds have increased recoil, velocity, and penetration. For rounds like the .38 special, the +P rounds fall between an average .38 special and a .357 magnum. Most often seen as handgun defensive rounds, these should only be used in weapons rated for them.
Match grade rounds are referring to rounds carefully calculated to be incredibly accurate at long ranges. As the name suggests, these rounds are most commonly used in competition. These rounds see limited use by police and military; they are used most often by the unit’s snipers. The quality of these rounds is above and beyond the quality of normal rounds, and the typical price reflects that.
A trace round is a special loaded round with a form of phosphorus that ignites when the round is fired. This phosphorus leaves a bright trail behind round, allowing the shooter to see where his round is going. Most commonly used by machine guns in the military to observe the beaten zone of rounds, and to make adjustments during extended firing. These rounds are more of a novelty for civilian shooters. Take caution when firing these rounds as they can start fires. I’ve personally ignited many machine gun ranges, and even fields in Afghanistan, using a machine gun with tracers.
A center fire round is one where the primer is located in the center of the round head case. This can be replaced and the case can be used over again. Center fire has become the dominant round in shooting today. Nearly all rounds are center fire, with the exception of rounds like the variants of the .22 calibers.
Rim fire is a reference to where the firing pin strikes the primer. The primer of a rim fire round is basically a percussion cap and when struck, ignites the propellant and sends the round down range. Rim fire rounds cannot be reloaded. Rim fire rounds have been largely replaced by center fire rounds, and only smaller calibers like the .22 and .17 retain a rim fire ignition system.
Shotgun rounds are a different beast. They are much different than rifle and handgun rounds and deserve their own section. I will not go too far in depth with these as this article is meant to be a quick reference guide rather than a detailed explanation.
A shotgun gauge is a reference to a very old method of measurement used to express the diameter of the barrel. Gauge refers to the size of a sphere of lead that will fit the bore of the firearm and is expressed as a fraction of a pound when weighed. Thus, a 12 gauge is called that because a lead sphere the same diameter of the bore weighs 1/12th of a pound. The most important thing to remember is that the lower the gauge, the larger the bore, therefore the more powerful the shotgun. Therefore a 12 gauge is larger than a 20 gauge. All shotgun rounds are measured in gauge, except for the .410.
Buckshot refers to a larger size of shot used to take down medium game or for self-defense. Buckshot is measure from 4 to triple aught (represented as 000). Triple aught is the largest and 4 is known as the smallest acceptable buckshot. Triple aught is a reference to the size of shot, not the amount. Triple aught is .36 caliber and #4 is .24 caliber.
Birdshot is round designed for sporting events and small game. These rounds are numbered from 4 to 9, with # 4 being the largest and #9 being the smallest. Number 9 through 7 ½ are used most often for skeet and trap shooting respectfully, but can be used for bird or squirrels. Larger loads are chosen for larger game or pests, such as raccoons, foxes, and coyotes.
Note that there is a #4 shot in both buckshot and birdshot, but they are not the same sized pellet. Again, #4 buckshot is a .24 caliber pellet while #4 birdshot is a .13 caliber pellet. These two shotgun shells are not the same.
Slugs differentiate from shot by being a solid round. Often very heavy and powerful, used to take down game and serve some self-defense purposes. Slugs are used when a shooter armed with a shotgun needs to reach out farther than buckshot will allow. In certain localities where hunting with rifles is not allowed due to homes being within a certain range, slugs are the preferred round. Slugs are perfect for shooting at around a hundred yards, and have been proven to hit targets even beyond that.
This was my quick class on some different bullet terms. I didn’t want to go too deep because we’d be here all day with terms like “boat tail” and “spitzer round” or comparing how much shot you can fit per inch of a shotgun round. This list should get you started though.