
In firearms, a trapdoor is a form of breech-loading mechanism for
rifle
A rifle is a long gun, long-barreled firearm designed for accurate shooting and higher stopping power, with a gun barrel, barrel that has a helical or spiralling pattern of grooves (rifling) cut into the bore wall. In keeping with their focus o ...
s in which a hinged
breechblock
A breechblock (or breech block) is the part of the firearm action that closes the breech of a breech loading weapon (whether small arms or artillery) before or at the moment of firing. It seals the breech and contains the pressure generated by ...
rotates up and forward, resembling the movement of a
trapdoor
A trapdoor or hatch is a sliding or hinged door that is flush with the surface of a floor, ceiling, or roof. It is traditionally small in size. It was invented to facilitate the hoisting of grain up through mills, however, its list of uses has ...
. The Springfield models
1865
Events
January
* January 4 – The New York Stock Exchange opens its first permanent headquarters at 10-12 Broad near Wall Street, in New York City.
* January 13 – American Civil War: Second Battle of Fort Fisher – Unio ...
and
1873
Events January
* January 1
** Japan adopts the Gregorian calendar.
** The California Penal Code goes into effect.
* January 17 – American Indian Wars: Modoc War: First Battle of the Stronghold – Modoc Indians defeat the Unit ...
were best known for first employing this type of action.
Specifications

The ''trapdoor'' ''mechanism'' employed a hinged
breechblock
A breechblock (or breech block) is the part of the firearm action that closes the breech of a breech loading weapon (whether small arms or artillery) before or at the moment of firing. It seals the breech and contains the pressure generated by ...
that rotated up and forward, resembling the movement of a
trapdoor
A trapdoor or hatch is a sliding or hinged door that is flush with the surface of a floor, ceiling, or roof. It is traditionally small in size. It was invented to facilitate the hoisting of grain up through mills, however, its list of uses has ...
, to open the breech of the rifle and permit insertion of a cartridge. The hinged breechblock caused these rifles to be named "Trapdoor Springfields".
The conversion from
musket
A musket is a muzzle-loaded long gun that appeared as a smoothbore weapon in the early 16th century, at first as a heavier variant of the arquebus, capable of penetrating plate armour. By the mid-16th century, this type of musket gradually dis ...
to
breechloader
A breechloader is a firearm in which the user loads the ammunition from the breech end of the barrel (i.e., from the rearward, open end of the gun's barrel), as opposed to a muzzleloader, in which the user loads the ammunition from the ( muzz ...
was done by milling open the barrel's breech section and inserting a hinged ''trapdoor'' fastened to the top of the barrel. A thumb-operated cam latch at the rear of the breechblock held it shut when in closed position. The rack-type system extractor was withdrawn automatically as the breechblock was opened and snapped back at the end of its stroke. The firing pin was housed within the breechblock. The hammer nose was flattened to accommodate the firing pin.
Approximately 5,000 Civil War
Model 1861 rifled musket
A rifled musket, rifle musket, or rifle-musket is a type of firearm made in the mid-19th century. Originally the term referred only to muskets that had been produced as a smoothbore weapon and later had their Gun barrel, barrels replaced with Ri ...
s were converted at the Springfield Armory in 1866. It soon became apparent that many of the small working parts in the breech system were not going to have a long service life, and the action was too complicated for normal service use. Therefore, before the Model 1865 production order was completed, a less complex rifle was already being tested. This caused the Model 1865 to be called the "First Allin", and the following revised model, the
Springfield Model 1866, to be called the "Second Allin".
The Springfield model 1865 fired a rimfire .58-60-500 cartridge (.58 inch bullet, of black powder), the caliber matching that of the Civil War
Minié ball
The Minié ball, or Minie ball, is a type of hollow-based bullet designed by Claude-Étienne Minié for muzzle-loaded, rifled muskets. Invented in 1846 shortly followed by the Minié rifle, the Minié ball came to prominence during the Crime ...
, which was originally used in these rifles.
The Model 1865 quickly became obsolete, and most of them were sold in the 1870s to several American arms dealers. At the time, there was a large demand in the US for shorter cadet-style rifles. To satisfy this need, these dealers cut the barrels and stocks to make short rifles with 33-inch and 36-inch barrel lengths. Likewise, the stock wrists were often thinned for cadet use.
Selection process

In 1872–1873 a military board, headed by Brigadier-General
Alfred H. Terry, conducted an examination and trial of 99 rifles from several domestic and foreign manufacturers, including those from
Springfield,
Sharps,
Peabody,
Whitney,
Spencer,
Remington, and
Winchester
Winchester (, ) is a City status in the United Kingdom, cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government Districts of England, district, at the western end of the South Downs N ...
pursuant to the selection of a breech-loading system for rifles and carbines for the U.S. Military.
The trials included tests for: accuracy, dependability,
rate of fire
Rate of fire is the frequency at which a specific weapon can fire or launch its projectiles. This can be influenced by several factors, including operator training level, mechanical limitations, ammunition availability, and weapon condition. In m ...
, and ability to withstand adverse conditions. Both single-shot and
magazine
A magazine is a periodical literature, periodical publication, print or digital, produced on a regular schedule, that contains any of a variety of subject-oriented textual and visual content (media), content forms. Magazines are generally fin ...
-equipped systems were considered, but, at the time, the single-shot was deemed to be more reliable. Firing tests were held at the
Springfield Armory
The Springfield Armory, more formally known as the United States Armory and Arsenal at Springfield located in the city of Springfield, Massachusetts, was the primary center for the manufacture of United States military firearms from 1777 until ...
and
Governor's Island where the average rate of fire for the Springfield was 8 rounds per minute for new recruits and 15 rounds per minute for experienced soldiers. The board recommended "No. 99 Springfield" which became the ''model 1873''.
After considerable testing, the prototype developed by Erskine S. Allin of the government-operated
Springfield Armory
The Springfield Armory, more formally known as the United States Armory and Arsenal at Springfield located in the city of Springfield, Massachusetts, was the primary center for the manufacture of United States military firearms from 1777 until ...
was chosen for its simplicity and the fact that it could be produced by the modification of existing Springfield
Model 1863 muskets. These modifications cost about $5 per rifle, which was a significant savings at a time when new rifles cost about $20 each. Patent No. 49,959 was issued to Erskine S. Allin on September 19, 1865, describing the design.
In fiction
The Springfield rifles with this modification. ''¨The Gun That Made One Man The Equal Of Five¨,'' come out in the epilogue of the action in the film
Springfield Rifle (used to stop the thieves stealing horses for the
Confederates).
See also
*
Wänzl rifle, Austro-Hungarian service weapons
*
M1867 Russian Krnka
*
Infanteriegewehr Modell 1842
The Infanteriegewehr Modell 1842 () was one of the first standardised service rifles used by the Swiss armed forces. It was introduced in 1842 as a result of a decision by the authorities of the Old Swiss Confederacy to standardise the weapons of ...
, earlier trapdoor action gun
Bibliography
*''Historical Dictionary of the U.S. Army'' by Jerold E. Brown, published by Greenwood Publishing Group, 2001
*''The .58 and .50 Caliber Rifles and Carbines of the Springfield Armory'' by Richard A. Hosmer, published by North Cape Publications, May 2006
References
External links
{{commonscat, Trapdoor action
Article on TrapdoorHistory and an animated gif showing the action movement.
at Trapdoor Collector
Firearm actions