Cartridge (firearms) - Bullet Design Types

Bullet Design Types

• 12 gauge/70 mm standard shotgun buckshot ammunition loads. Listed here from largest to smallest shot size. Loads typically offered in the 70 mm length hull (many other loading options are available).

000 Buck: 8 lead pellets (0.36 in/9.1 mm)

00 Buck: 9 lead pellets (0.33 in/8.4 mm, 12 pellets for Magnum load)

0 Buck: 12 lead pellets (0.32 in/8.1 mm)

1 Buck: 16 lead pellets (0.30 in/7.6 mm, 20 pellets for Magnum load)

4 Buck: 27 lead pellets (0.24 in/6.1 mm)

• Shotgun slug: Slugs can be made of solid lead, copper, or a composite of any of various materials. Slugs are stabilized in flight by rifling in the barrel, which causes the slug to spin, or are stabilized as a dart is by the weight center of balance being forward of the aerodynamic center of balance, sometimes with assistance from fins. Solid or hollow-point slugs are available but, due to the relatively low velocity, hollow-point slugs often demonstrate relatively low expansion.
• Baton round: a generally non-lethal projectile fired from a riot gun.
• Armor Piercing (AP): A hard bullet made from steel or tungsten alloys in a pointed shape typically covered by a thin layer of lead and or a copper or brass jacket. The lead and jacket are intended to prevent barrel wear from the hard core materials. AP bullets are sometimes less effective on unarmored targets than FMJ bullets are. This has to do with the reduced tendency of AP projectiles to yaw (turn sideways after impact).
• Flat Nose Lead (FNL): Similar to the above, with a flattened nose. Common in Cowboy Action Shooting and plinking ammunition loads.
• Full Metal Jacket (FMJ): Made with a lead core surrounded by a full covering of brass, copper, or mild steel. These usually offer very little deformation or terminal performance expansion, but will occasionally yaw (turn sideways). Despite the name, a FMJ bullet typically has an exposed lead base, which is not visible in an intact cartridge.
• Glaser Safety Slug: The Glaser Safety Slug dates back to the early 1970s. The inventor, Colonel Jack Cannon, named it for his friend Armin Glaser. Over the years, these projectiles have evolved from crude, hand-produced examples to mass-production; however, the basic concept has remained the same: copper jackets filled with bird shot and covered by a crimped polymer endcap. Upon impact with flesh, the projectile is supposed to fragment, with the birdshot spreading like a miniature shotgun pattern. The standard "Blue" Glaser uses a rather fine birdshot that only gives 5 to 6 inches (130–150 mm) of penetration in flesh. The "Silver" Glaser adds another 1 to 2 inches (30–50 mm) of penetration with the use of slightly larger birdshot. Due to reduced penetration in flesh, some have theorized that the Glaser would be ideal where over-penetration of a projectile could be hazardous to bystanders. For instance, the Glaser might be entirely contained within an arm. However, for the same reasons, terminal performance of Glaser bullets can vary dramatically, producing impressive successes and equally spectacular failures depending on the angle at which the target is struck. Glancing hits on hard surfaces will result in fragmentation, reducing the risk of ricochets. However, the Glaser can penetrate barriers such as drywall, plywood, and thin sheet metal if struck nearly head on.
• Jacketed Hollow Point (JHP): Soon after the invention of the JSP, Woolwich Arsenal in Great Britain experimented with this design even further by forming a hole or cavity in the nose of the bullet while keeping most of the exterior profile intact. These bullets could theoretically deform even faster and expand to a larger diameter than the JSP. In personal defense use, concerns have arisen over whether clothing, especially heavy materials like denim, can clog the cavity of JHP bullets and cause expansion failures.
• Jacketed Soft Point (JSP): In the late 19th century, the Indian Army at Dum-Dum Arsenal, near Calcutta, developed a variation of the FMJ design where the jacket did not cover the nose of the bullet. The soft lead nose was found to expand in flesh while the remaining jacket still prevented lead fouling in the barrel. The JSP roughly splits the difference between FMJ and JHP. It gives more penetration than JHP but has more stopping power than the FMJ.
• Round Nose Lead (RNL): An unjacketed lead bullet. Although largely supplanted by jacketed ammunition, this is still common for older revolver cartridges. Some hunters prefer roundnose ammunition for hunting in brush because they erroneously believe that such a bullet deflects less than sharp-nosed spitzer bullets, regardless of the fact that this belief has been repeatedly proven not to be true. Refer to American Rifleman magazine.
• Total Metal Jacket (TMJ): Featured in some Speer cartridges, the TMJ bullet has a lead core completely and seamlessly enclosed in brass, copper or other jacket metal, including the base. According to Speer literature, this prevents hot propellant gases from vaporizing lead from the base of the bullet, reducing lead emissions. Sellier & Bellot produce a similar version that they call TFMJ, with a separate end cap of jacket material.
• Wadcutter (WC): Similar to the FNL, but completely cylindrical, in some instances with a slight concavity in the nose. This bullet derives its name from its popularity for target shooting, because the form factor cuts neat holes in paper targets, making scoring easier and more accurate and because it typically cuts a larger hole than a round nose bullet, a hit centered at the same spot can touch the next smaller ring and therefore score higher.
• Semi Wad Cutter (SWC) identical to the WC with a smaller diameter flap pointed conical or radiused nose added. Has the same advantages for target shooters but is easier to load into the gun and works more reliably in semi-automatic guns. This design is also superior for some hunting applications.
• Truncated Cone, Round Nose Flat Point, etc. Descriptive of typical modern commercial cast bullet designs.

The Hague Convention of 1899 bans the use of expanding projectiles against the military forces of other nations. Some countries accept this as a blanket ban against the use of expanding projectiles against anyone, while others use JSP and HP against non-military forces such as terrorists and criminals.