Buckshot was consistant with evolution in the development of small arms projectiles. The use of shot evolved from the common use of small stones which were poured down a muzzle loaders barrel, replacing a solid ball projectile. This technique was used for antipersonnel applications as well as hunting small game. As availability of lead became more prevalent it was used to form "swan drops", small dribbles of lead poured into water and used in place of small stones. In the progression of the industrial developments of ammunition, small projectile molds were produced to create spherical ball ammunition for rifles and pistols. This development led to the general use of spherical shot in large calibre muskets, leading to the first standardization of buckshot ammunition.
Buckshot ammunition was first standardized during the United States Civil War of 1860-1865. Arsenal production of ammunition for both sides of the conflict produced buckshot cartridges, consisting of a load of powder under a stack of 12 spherical shot arranged in layers of 3 balls, held within a linen or paper wrap. This loading configuration has remained consistant from the time of the initial standardization during the mid 1800's to the present day, over 150 years. Buckshot was standardized for the second time during World War Two using 9 spherical shot arranged in layers of 3 balls, assembled within a brass cartridge case. The modern example of 00 buckshot differs little from the standard musket buckshot in loading, except for the self contained cartridge case with integral ignition primer, with the exception of the late addition of granulated shot buffer.
Buckshot has an aerodynamic and terminal performance far below high velocity fin stabilized flechette projectiles. Upon firing interior setback forces have an extreme distortion on the spherical shape of the buckshot projectile, and during flight collisions along the axis of projection add distortions. Regardless of the addition of granulated plastic buffers or flash copper plating distortion of the lead projectiles is unavoidable. This cumulative effect creates an areodynamic form which is very roughly spherical, but so distorted as to provide no consistant predictable ballistic performance for velocity, grouping or terminal effect. Being a roughly spherical form the buckshot terminal performance is graduated by the vital nature of the target structure encountered, such as dense tissue or bone, and tends to traverse through the target along with it's residual kinetic energy. The ability of buckshot to traverse some dense barrier materials such as structural timber or tree limbs and branches is one positive aspect for the projectile, however this may be of limited value due to the remaining low residual energy for target penitration.
Flechettes are fin stabilized projectiles manufactured from steel, and flechette ammunition is an assembly of 20 flechettes within a conventional cartridge case. Flechette projectiles have aerodynamic and terminal performance far above conventional buckshot. Interior setback forces have no effect on flechettes upon firing, allowing the projectile to maintain it's shape and ballistic coefficent from discharge to terminal impact. The absence of distortion during firing and flight allow predictable ballistic performance for velocity, grouping and terminal effect. Flechettes have superior terminal performance to a roughly spherical soft lead buckshot. The flechettes steel form maintains it's rigidity in flight and looses it's rigidity upon terminal impact. As the flechette travels through dense tissue and bone it will begin to bend along the unsupported shaft portion from residual inertia, traversing sideways or hooking through the remaining tissue along the axis of impact, imparting all remaining kinetic energy to the target. The flechette passes readily through foliage and deposits little energy to the vegetation because of the penitrating pointed tip. When the flight path passes through vegetation, such as brush or tree branches, the flechettes may be slightly deflected with a resulting yaw or tumbling that improves immediate energy distribution on impact. Flechettes have limited ability to traverse through the dense barrier materials that may be over penitrated by buckshot, and is one consideration for flechette projectile use. This penitration effect resulting from the flechettes immediate distribution of kinetic energy may be advantageous in selective targeting for certain environments.
During the United States Vietnam War of 1965-1972 shotguns played an active role with ground forces and buckshot and flechette ammunition were actively evaluated for combat effectiveness. Combat evaluations from May 1967 to February 1968 were made with flechettes, M162 00 buckshot, and XM257 #4 buckshot. Flechette ammunition indicated a high lethality at all ranges with several one shot kills at engagement ranges to 100 yards, flechettes were prefered by combatants equally to 00 buckshot during this test phase. Flechette ammunition and 00 buckshot were also equally prefered over the issued XM257 #4 buckshot, which proved ineffective under combat conditions, lacking the penitration and terminal performance of either flechettes or 00 buckshot. Adoption of a standardized flechette cartridge was hindered by the United States govenment decision to begin disengaging from the Vietnam War. Flechette superiority to buckshot has proven manifest for all aspects of performance in velocity, grouping, and terminal effects.
