Semiwadcutter
Encyclopedia
A semiwadcutter or SWC is a type of all-purpose bullet
commonly used in revolver
s. The SWC combines features of the wadcutter
target bullet and traditional round nosed revolver bullets, and is used in both revolver and pistol
cartridges for hunting
, target shooting, and plinking
. Full wadcutters frequently have problems feeding from magazines reliably in automatics, so SWCs may be used when a true WC is desired but cannot be used for this reason.
The basic SWC design consists of a roughly conical nose, truncated with a flat point (called a meplat), sitting on a cylinder (A at right). The base of the cone is slightly smaller in diameter than the cylinder, leaving a sharp shoulder. The flat nose punches a clean hole in the target, rather than tearing it like a round nose bullet would, and the sharp shoulder enlarges the hole neatly, allowing easy and accurate scoring of the target. The SWC design offers better external ballistics
than the wadcutter, as its conical nose produces less drag than the flat cylinder. A typical modification is to alter the conical section to make the sides concave, to reduce the bullet mass, or convex, to increase it. B shows a concave sided SWC, typical of a lightweight .45 ACP
bullet used in bullseye shooting
. The concave sides reduce the bullet weight, and thus the recoil, while keeping the overall length of the bullet long enough to feed reliably in a semi-automatic pistol such as the M1911
commonly found in bullseye competitions.
Some of the most famous SWC designs were developed by Elmer Keith
for use in handgun hunting. These designs (C) use a wider front, and convex sides on the "cone" in front. This puts more weight in the front of the bullet, allowing a heavier bullet with no reduction in case capacity. Since Keith was a prime motivating force in the development of the first magnum
handgun cartridge, the .357 Magnum
, he was very interested in maximizing the amount of case volume for the slower burning powders needed to push heavy bullets at high velocities. The choice of bullet for the .357 Magnum cartridge varied during its development. During the development at Smith & Wesson, the original Keith bullet was modified slightly, to the form of the Sharpe bullet, which itself was based upon the Keith bullet, but which had 5/6 of the bearing surface of the Keith bullet, Keith bullets typically being made oversized and sized down. Winchester, however, upon experimenting further during the cartridge development, modified the Sharpe bullet shape slightly, while keeping the Sharpe contour of the bullet. The final choice of bullet for the .357 Magnum was thus based on the earlier Keith and Sharpe bullets, while additionally having slight differences from both.
The Keith style SWC has been taken even further, to produce designs that are nearly wadcutters in shape (D), but are intended for large game hunting with handguns. These have nearly cylindrical noses, which are as long as the firearm chamber allows, and just slightly smaller than bore diameter so they will easily chamber. The massive nose provides a large surface area for producing large wound channels, resulting in rapid incapacitation, and the heavy bullet provides excellent penetration. The wide nose is less prone to deformation than a narrow nose, allowing the bullet to keep its shape and continue to penetrate even if it encounters bone.
Originally Keith specified a meplat that was 65% of the bullet caliber, but later increased it to a 70% meplat. The other distinguishing characteristics of a "Keith-style" SWC are a double radius ogive, beveled crimp groove, three equal width driving bands, wide square bottomed grease groove, and a plain base with sharp corners. The wide forward driving band helps keep the bullet aligned as it jumps across the cylinder gap. Because of the three wide equal width driving bands, the total bearing surface is half the length of the bullet. The relatively large bearing surface helps the Keith-style SWC to be an inherently accurate bullet, and minimizes leading from gas blow-by. The wide square bottom grease groove holds ample lubricant.
Bullet
A bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives, but damage the intended target by impact and penetration...
commonly used in revolver
Revolver
A revolver is a repeating firearm that has a cylinder containing multiple chambers and at least one barrel for firing. The first revolver ever made was built by Elisha Collier in 1818. The percussion cap revolver was invented by Samuel Colt in 1836. This weapon became known as the Colt Paterson...
s. The SWC combines features of the wadcutter
Wadcutter
A wadcutter is a special-purpose bullet specially designed for shooting paper targets, usually at close range and at subsonic velocities typically under 800 ft/s . They are often used in handgun and airgun competitions...
target bullet and traditional round nosed revolver bullets, and is used in both revolver and pistol
Pistol
When distinguished as a subset of handguns, a pistol is a handgun with a chamber that is integral with the barrel, as opposed to a revolver, wherein the chamber is separate from the barrel as a revolving cylinder. Typically, pistols have an effective range of about 100 feet.-History:The pistol...
cartridges for hunting
Hunting
Hunting is the practice of pursuing any living thing, usually wildlife, for food, recreation, or trade. In present-day use, the term refers to lawful hunting, as distinguished from poaching, which is the killing, trapping or capture of the hunted species contrary to applicable law...
, target shooting, and plinking
Plinking
Plinking refers to informal target shooting done at non-traditional targets such as tin cans, glass bottles, and balloons filled with water. The term is an onomatopoeia of the sound a bullet or other projectile makes when hitting a tin can, or other similar target, referring to the sharp, metallic...
. Full wadcutters frequently have problems feeding from magazines reliably in automatics, so SWCs may be used when a true WC is desired but cannot be used for this reason.
External ballistics
External ballistics is the part of the science of ballistics that deals with the behaviour of a non-powered projectile in flight. External ballistics is frequently associated with firearms, and deals with the behaviour of the bullet after it exits the barrel and before it hits the target.-Forces...
than the wadcutter, as its conical nose produces less drag than the flat cylinder. A typical modification is to alter the conical section to make the sides concave, to reduce the bullet mass, or convex, to increase it. B shows a concave sided SWC, typical of a lightweight .45 ACP
.45 ACP
The .45 ACP , also known as the .45 Auto by C.I.P., is a cartridge designed by John Browning in 1904, for use in his prototype Colt semi-automatic .45 pistol and eventually the M1911 pistol adopted by the United States Army in 1911.-Design and history:The U.S...
bullet used in bullseye shooting
Bullseye (shooting competition)
Bullseye, also known as conventional pistol, is a shooting sport in which participants shoot handguns at paper targets at fixed distances and time limits. A number of organizations, including the NRA and Civilian Marksmanship Program in the United States, have established rules and keep records for...
. The concave sides reduce the bullet weight, and thus the recoil, while keeping the overall length of the bullet long enough to feed reliably in a semi-automatic pistol such as the M1911
M1911
The M1911 is a single-action, semi-automatic, magazine-fed, and recoil-operated handgun chambered for the .45 ACP cartridge. John M. Browning designed the firearm which was the standard-issue side arm for the United States armed forces from 1911 to 1985. The M1911 is still carried by some U.S....
commonly found in bullseye competitions.
Some of the most famous SWC designs were developed by Elmer Keith
Elmer Keith
Elmer Keith was an Idaho rancher, firearms enthusiast, and author. Keith was instrumental in the development of the first magnum revolver cartridge, the .357 Magnum, as well as the later .44 Magnum and .41 Magnum cartridges.-Personality and life:Keith's trademarks were his cigars, his ten-gallon...
for use in handgun hunting. These designs (C) use a wider front, and convex sides on the "cone" in front. This puts more weight in the front of the bullet, allowing a heavier bullet with no reduction in case capacity. Since Keith was a prime motivating force in the development of the first magnum
Magnum
Magnum may refer to several things:* Moses Magnum, a Marvel Comics villain*Magnum, P.I., a television series** Thomas Magnum, the lead character...
handgun cartridge, the .357 Magnum
.357 Magnum
The .357 S&W Magnum , or simply .357 Magnum, is a revolver cartridge created by Elmer Keith, Phillip B. Sharpe, Colonel D. B. Wesson of firearms manufacturer Smith & Wesson, and Winchester. It is based upon Smith & Wesson's earlier .38 Special cartridge. The .357 Magnum cartridge was introduced in...
, he was very interested in maximizing the amount of case volume for the slower burning powders needed to push heavy bullets at high velocities. The choice of bullet for the .357 Magnum cartridge varied during its development. During the development at Smith & Wesson, the original Keith bullet was modified slightly, to the form of the Sharpe bullet, which itself was based upon the Keith bullet, but which had 5/6 of the bearing surface of the Keith bullet, Keith bullets typically being made oversized and sized down. Winchester, however, upon experimenting further during the cartridge development, modified the Sharpe bullet shape slightly, while keeping the Sharpe contour of the bullet. The final choice of bullet for the .357 Magnum was thus based on the earlier Keith and Sharpe bullets, while additionally having slight differences from both.
The Keith style SWC has been taken even further, to produce designs that are nearly wadcutters in shape (D), but are intended for large game hunting with handguns. These have nearly cylindrical noses, which are as long as the firearm chamber allows, and just slightly smaller than bore diameter so they will easily chamber. The massive nose provides a large surface area for producing large wound channels, resulting in rapid incapacitation, and the heavy bullet provides excellent penetration. The wide nose is less prone to deformation than a narrow nose, allowing the bullet to keep its shape and continue to penetrate even if it encounters bone.
Originally Keith specified a meplat that was 65% of the bullet caliber, but later increased it to a 70% meplat. The other distinguishing characteristics of a "Keith-style" SWC are a double radius ogive, beveled crimp groove, three equal width driving bands, wide square bottomed grease groove, and a plain base with sharp corners. The wide forward driving band helps keep the bullet aligned as it jumps across the cylinder gap. Because of the three wide equal width driving bands, the total bearing surface is half the length of the bullet. The relatively large bearing surface helps the Keith-style SWC to be an inherently accurate bullet, and minimizes leading from gas blow-by. The wide square bottom grease groove holds ample lubricant.