Rat-shot (or snake shot) is very small lead shot (typically #12 – 1.3 mm (0.05")) loaded in cartridges for use in rifled firearms as opposed to more traditional smoothbores such as shotguns. Rat-shot cartridges allow one to use a handgun or rifle as a low power shotgun for short-range use. Cartridges loaded with rat-shot are often called shotshells. The most common cartridges loaded with rat-shot are the .22 Long Rifle and certain pistol or revolver cartridges. Shotshell cartridges known to be available for hand guns include: .22 LR, .22 Magnum, .38 Special, 9×19mm Luger, .40 Smith & Wesson, .44 Special, .45 ACP and .45 Colt. The CCI .22 LR shotshell holds 1/15 ounce of #12 shot; the CCI .45 Colt shotshell holds 1/3 ounce of #9 shot. The smaller shot size typical of .22 shotshells is sometimes called "dust shot" and is used mainly by collectors of bird specimens.
Rat-shot is generally used for shooting at snakes, rodents, and other small animals at very close range. It is used by farmers in rifles for the control of birds flying inside of barns and sheds, as well as for killing rats, for the simple reason that rat-shot will not damage the metal roof of a barn or the metal sides of a shed, while still being effective against small pests at close distances. Rat-shot is often used in 22 caliber rifles to train new shooters in the use of a shotgun and as a first step in bird dog training for the dog to get used to loud noises.
Rat-shot cartridges are best used in dedicated smoothbore firearms such as Marlin Firearms' Model 25MG Garden Gun, but can still provide suitable patterns of shot from rifled barrels at short ranges. Since smoothbore firearms with barrels under eighteen inches (in the US) may be classified as sawed off shotguns, handguns used with rat-shot usually have rifled barrels. The Thompson Center Arms Contender pistols offered barrels in some calibers, such as .357 Magnum and .44 Magnum, in configurations that contained special straight rifled choke tubes to improve the patterns produced by the rifled barrels when shooting rat-shot cartridges. The maximum effective killing range of rat-shot cartridges is limited, typically being less than 10 to 16 feet (3 to 5 meters).
Rat-shot is also used in some types of frangible ammunition, such as the Glaser Safety Slug which acts as a solid bullet until it impacts a target and has the effective killing range of a solid bullet. In these bullets, the shot is glued or sintered together inside a thin shell to form a projectile that fragments readily upon impact, reducing penetration, risk of ricochet and the collateral damage associated with over-penetration and ricochet.
While some makes of rimfire ratshot cartridges somewhat resemble traditional shotgun shells, with a brass case crimped closed, many other types of rimfire and nearly all centerfire rat-shot cartridges use a hollow plastic capsule, often shaped like a bullet to aid in feeding, which holds the shot. This plastic case shatters during firing, and allows the shot to disperse after it exits the muzzle. There are reports of the plastic casing shattering when being fed from a magazine. Crimped cases do not exhibit this problem but can fail to extract in some semi-automatic guns.
Notes and references
- Reed, C.K. & C.A. Reed (1914). Guide to taxidermy. pp. 22–23.
- Barrett, Peter (1988). "A Gathering of Chinooks". Field & Stream. 92 (11): 62.
- Horton, David (1971). "New Handgun Shotshell". Field & Stream. 76 (7): 16–18.
- Warner, Ken (1986). Gun Digest: 1987 Annual Edition. DBI Books. pp. 38–43.
- Brister, Bob (1975). "Two Magnum movies and Other News". Field & Stream. 79 (11): 129.
- Handgun Shot Loads Work For Pests But Not Defense, Gun Week, 2005 (dead link 28 August 2017)