K31
Encyclopedia
The Karabiner Model 1931 (K31) is a magazine
-fed, straight-pull bolt-action rifle. It was the standard issue rifle of the Swiss armed forces
from 1933 until 1958, though examples remained in service into the 1970s. It has a 6-round removable magazine
, and is chambered for the 7.5x55mm Swiss (also known as Gewehrpatrone 1911, GP11, or unofficially 7.5x55mm Schmidt Rubin), a cartridge with ballistic qualities similar to the .308 Winchester
cartridge. Each rifle included a 6 round detachable box magazine with matching engraved serial number. A stripper clip loads the magazine from the top of the receiver.
The often quoted but incorrect name of "Schmidt-Rubin
" comes from two designers: Rudolf Schmidt, who designed the action for Switzerland's 1889 and 1896 rifles, and Lt. Col. Eduard Rubin
, who designed the ammunition.
Although the K31 is a straight-pull carbine
like many other Swiss rifles, it was not designed by Rudolf Schmidt (1832-1898) as he was not alive to do so. The K31 was a totally new design by Eidgenossische Waffenfabrik in Bern, Switzerland under Colonel Furrer, and the gun does not have the Schmidt-designed 1889 or 1896 action. The first 200 K31s were made in May 1931 for troop trials (serials 500,001 - 500,200), thus the model number of 1931.
is pulled directly back, then pushed forward to cycle the action between shots, rather than being turned and pulled back and forth, as in the Mosin Nagant pattern rifles such as the M1891, or as in the more well known Mauser
pattern rifles such as the K98k.
K31s are also noted for their excellent accuracy and quality. The Swiss considered individual marksmanship to be of utmost importance. Therefore, the K31 was made with tight tolerance
s and excellent overall craftsmanship. Many shooters are able to achieve one minute of arc
with unmodified K31s. This means that a group of bullets shot at 100 yards will stay within a 1" diameter area, a group at 200 yards will stay within 2", etc. This is achievable with factory sights. Clamp-on sighting options for scopes and competition sights make it easier to mount a scope on the receiver.
K31s use a unique formed phenolic resin embedded paper charging clip with a tinned metal edge holding six rounds. Where as most charger clips only hold the end of the round, the K31 charger nearly covers the entire cartridge. The clip has a guide slot wide enough for a gloved thumb to force rounds down and into the magazine in one smooth motion.
Many collectors of the K31 have removed the butt plate and recovered a small tag of plasticized paper from beneath it. This slip contains the name and address of the Swiss citizen to whom the rifle was issued. In some cases, collectors have used the information to contact the previous owners, and have recounted the details of those encounters on a variety of collector's web forums.
The standard sights on a K31 are open sights that can be adjusted for both windage and elevation. The rear sight is graduated from 100 up to 1500 meters in 100 meter increments. The sight line can be adjusted with a front sight adjustment tool. Moving the front post 1 mm horizontally results in a 12 cm shift at 300 m. To adjust the average height of the point of impact 5 front posts ranging from 5.9 to 7.1 mm height in 0.3 mm increments are available. The change in impact height from one front site to the next is 16 cm at 300 m. Starting at 300 meters the shooter should aim just below the bottom of the target, so that the front sight's post is out of the way. Mounting a scope conventionally is not easily done because of the design of the action, but there are specialized scope mounts available.
As the Swiss still have a militia army where soldiers sometimes keep their rifles for a lifetime many aftermarket sights were available, Waffenfabrik Bern made the "S" and "K" (Klammer) diopter sights, Wyss makes the "W" diopter and Furter, Haemmerli and Gruenig and Elmiger made now rare special windage and elevation fine-correctors, Sahli and many other made elevation fine correctors and these days a company by the name of Swiss Products in the USA makes a clamp-on diopter which was recently approved for use at official Swiss shooting matches.
, the K31 was replaced by the SIG 510
in 1958. As of 2006, the K31 is readily available from most military surplus
vendors. As noted above, the stocks are usually in average condition, but the barrel and bolt assembly are usually in very good condition because the Swiss used a special gun grease instead of gun cleaning oil.
As of 2010 the Swiss arsenals are long sold out and the guns now available on the US-market are ex-Swiss-civilian owned guns.
Magazine (firearm)
A magazine is an ammunition storage and feeding device within or attached to a repeating firearm. Magazines may be integral to the firearm or removable . The magazine functions by moving the cartridges stored in the magazine into a position where they may be loaded into the chamber by the action...
-fed, straight-pull bolt-action rifle. It was the standard issue rifle of the Swiss armed forces
Military of Switzerland
The Swiss Armed Forces perform the roles of Switzerland's militia and regular army. Under the country's militia system, professional soldiers constitute about 5 percent of military personnel; the rest are male citizen conscripts 19 to 34 years old...
from 1933 until 1958, though examples remained in service into the 1970s. It has a 6-round removable magazine
Magazine (firearm)
A magazine is an ammunition storage and feeding device within or attached to a repeating firearm. Magazines may be integral to the firearm or removable . The magazine functions by moving the cartridges stored in the magazine into a position where they may be loaded into the chamber by the action...
, and is chambered for the 7.5x55mm Swiss (also known as Gewehrpatrone 1911, GP11, or unofficially 7.5x55mm Schmidt Rubin), a cartridge with ballistic qualities similar to the .308 Winchester
.308 Winchester
The .308 Winchester is a rifle cartridge and is the commercial cartridge upon which the military 7.62x51mm NATO centerfire cartridge is based. The .308 Winchester was introduced in 1952, two years prior to the NATO adoption of the 7.62x51mm NATO T65...
cartridge. Each rifle included a 6 round detachable box magazine with matching engraved serial number. A stripper clip loads the magazine from the top of the receiver.
The often quoted but incorrect name of "Schmidt-Rubin
Schmidt-Rubin
The Schmidt-Rubin rifles were a series of Swiss Army service rifles in use between 1889 and 1953. They are distinguished by the straight-pull bolt action invented by Rudolf Schmidt and use Eduard Rubin's 7.5x55mm rifle cartridge.-Schmidt-Rubin 1889:...
" comes from two designers: Rudolf Schmidt, who designed the action for Switzerland's 1889 and 1896 rifles, and Lt. Col. Eduard Rubin
Eduard Rubin
Lieutenant Colonel Eduard Rubin was a Swiss firearm designer who is most notable for inventing the full metal jacket bullet in 1882. His most famous cartridge was the 7.5x55mm Swiss. He served as director of the Swiss Federal Ammunition Factory and Research Center in Thun.-References:...
, who designed the ammunition.
Although the K31 is a straight-pull carbine
Carbine
A carbine , from French carabine, is a longarm similar to but shorter than a rifle or musket. Many carbines are shortened versions of full rifles, firing the same ammunition at a lower velocity due to a shorter barrel length....
like many other Swiss rifles, it was not designed by Rudolf Schmidt (1832-1898) as he was not alive to do so. The K31 was a totally new design by Eidgenossische Waffenfabrik in Bern, Switzerland under Colonel Furrer, and the gun does not have the Schmidt-designed 1889 or 1896 action. The first 200 K31s were made in May 1931 for troop trials (serials 500,001 - 500,200), thus the model number of 1931.
Distinctions
The K31 is noted for its straight-pull action, meaning that the boltBolt (firearm)
A bolt is a mechanical part of a firearm that blocks the rear of the chamber while the propellant burns.In manually-operated firearms, such as bolt-action, lever-action, and pump-action rifles and shotguns, the bolt is held fixed by its locking lugs during firing, forcing all the expanding gas...
is pulled directly back, then pushed forward to cycle the action between shots, rather than being turned and pulled back and forth, as in the Mosin Nagant pattern rifles such as the M1891, or as in the more well known Mauser
Mauser
Mauser was a German arms manufacturer of a line of bolt-action rifles and pistols from the 1870s to 1995. Mauser designs were built for the German armed forces...
pattern rifles such as the K98k.
K31s are also noted for their excellent accuracy and quality. The Swiss considered individual marksmanship to be of utmost importance. Therefore, the K31 was made with tight tolerance
Tolerance (engineering)
Engineering tolerance is the permissible limit or limits of variation in# a physical dimension,# a measured value or physical property of a material, manufactured object, system, or service,# other measured values ....
s and excellent overall craftsmanship. Many shooters are able to achieve one minute of arc
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....
with unmodified K31s. This means that a group of bullets shot at 100 yards will stay within a 1" diameter area, a group at 200 yards will stay within 2", etc. This is achievable with factory sights. Clamp-on sighting options for scopes and competition sights make it easier to mount a scope on the receiver.
K31s use a unique formed phenolic resin embedded paper charging clip with a tinned metal edge holding six rounds. Where as most charger clips only hold the end of the round, the K31 charger nearly covers the entire cartridge. The clip has a guide slot wide enough for a gloved thumb to force rounds down and into the magazine in one smooth motion.
Many collectors of the K31 have removed the butt plate and recovered a small tag of plasticized paper from beneath it. This slip contains the name and address of the Swiss citizen to whom the rifle was issued. In some cases, collectors have used the information to contact the previous owners, and have recounted the details of those encounters on a variety of collector's web forums.
Poor stock condition
The poor condition of many stocks was caused mostly by the hobnail shoes and rifle drills that were common. Post war beech stocks are more affected than the older walnut ones. Walnut stocks were treated with linseed oil and beech stocks got a shellac protective layer that easily dissolves in alcohol for (arsenal) repairs. Some of the older stocks are reported with both linseed and shellac.Sights
The standard sights on a K31 are open sights that can be adjusted for both windage and elevation. The rear sight is graduated from 100 up to 1500 meters in 100 meter increments. The sight line can be adjusted with a front sight adjustment tool. Moving the front post 1 mm horizontally results in a 12 cm shift at 300 m. To adjust the average height of the point of impact 5 front posts ranging from 5.9 to 7.1 mm height in 0.3 mm increments are available. The change in impact height from one front site to the next is 16 cm at 300 m. Starting at 300 meters the shooter should aim just below the bottom of the target, so that the front sight's post is out of the way. Mounting a scope conventionally is not easily done because of the design of the action, but there are specialized scope mounts available.
As the Swiss still have a militia army where soldiers sometimes keep their rifles for a lifetime many aftermarket sights were available, Waffenfabrik Bern made the "S" and "K" (Klammer) diopter sights, Wyss makes the "W" diopter and Furter, Haemmerli and Gruenig and Elmiger made now rare special windage and elevation fine-correctors, Sahli and many other made elevation fine correctors and these days a company by the name of Swiss Products in the USA makes a clamp-on diopter which was recently approved for use at official Swiss shooting matches.
Availability
As a standard service rifle of the Swiss armed forcesMilitary of Switzerland
The Swiss Armed Forces perform the roles of Switzerland's militia and regular army. Under the country's militia system, professional soldiers constitute about 5 percent of military personnel; the rest are male citizen conscripts 19 to 34 years old...
, the K31 was replaced by the SIG 510
SIG 510
The SIG SG 510 or Sturmgewehr 57 is an automatic rifle manufactured by Schweizerische Industrie Gesellschaft of Switzerland. It uses a similar roller-delayed blowback system to the H&K G3 and CETME rifles...
in 1958. As of 2006, the K31 is readily available from most military surplus
Military surplus
Military surplus are goods, usually matériel, that are sold or otherwise disposed of when no longer needed by the military. Entrepreneurs often buy these goods and resell them at surplus stores. Military surplus rarely includes weapons or munitions, though they are occasionally found in such stores...
vendors. As noted above, the stocks are usually in average condition, but the barrel and bolt assembly are usually in very good condition because the Swiss used a special gun grease instead of gun cleaning oil.
As of 2010 the Swiss arsenals are long sold out and the guns now available on the US-market are ex-Swiss-civilian owned guns.
Media
- A video of the K31 straight pull bolt in action: Media:k31.ogg
- In the film Shining ThroughShining ThroughShining Through is a 1992 British-American World War II film drama, directed and written by David Seltzer and starring Michael Douglas and Melanie Griffith, with Liam Neeson, Joely Richardson and John Gielgud in supporting roles. Although based on the novel of the same name by Susan Isaacs, the...
, a Swiss border guard, with his K31, shot a GermanNazi GermanyNazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
sniper firing at Ed and Linda as they were crossing over the Swiss border.
See also
- Schmidt-RubinSchmidt-RubinThe Schmidt-Rubin rifles were a series of Swiss Army service rifles in use between 1889 and 1953. They are distinguished by the straight-pull bolt action invented by Rudolf Schmidt and use Eduard Rubin's 7.5x55mm rifle cartridge.-Schmidt-Rubin 1889:...
- Antique gunsAntique gunsAn antique firearm is, loosely speaking, a firearm designed and manufactured prior to the beginning of the 20th century. The Boer War is often used as a cut-off event, although the exact definition of what constitutes an "antique firearm" varies from jurisdiction to jurisdiction...
- Steyr-Mannlicher M1895Steyr-Mannlicher M1895The Steyr-Mannlicher M1895 rifle is a bolt-action rifle, designed by Ferdinand Ritter von Mannlicher that used a refined version of his revolutionary straight-pull action. It was nicknamed the "Ruck-Zuck" by Landsers...
- An Austrian straight-pull bolt action rifle - Ross rifleRoss rifleThe Ross rifle was a straight-pull bolt-action 0.303 inch calibre rifle produced in Canada from 1903 until the middle of the First World War....
- An ill-fated Canadian straight-pull bolt action rifle - M1895 Lee NavyM1895 Lee NavyThe Lee Model 1895 was a straight-pull, cam-action magazine rifle adopted in limited numbers by the U.S. Navy and Marine Corps in 1895 as a first-line infantry rifle...
- An American straight-pull bolt action rifle
External links
- Swiss Rifles
- http://theswissriflesdotcommessageboard.yuku.com/ (the forum on the subject)
- Surplusrifle.com's articles on the K31
- Modern Firearms entry on the K31
- chuckhawks.com article on the K31
- Manufacture Dates of Swiss Schmidt-Rubin Rifles
- Webbased Tool to find the manufacture year based on the manufacturer serial number (German Website)