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A selective-fire firearm has at least two firearm modes, which are activated by means of a selector which varies depending on the weapon's design. Some selective-fire weapons have burst fire mechanisms to limit the maximum number of shots fired automatically in this mode. The most common limits are two or three rounds per trigger pull. Fully automatic fire refers to the ability for a weapon to fire continuously until the feeding mechanism is either emptied or the trigger is released. "Burst-capable" fire refers to the ability of a weapon to fire a small, fixed number of rounds (usually two or three) with one trigger pull. Semi-automatic refers to the ability to fire one round per trigger pull. The presence of selective-fire modes on firearms permits more efficient use of rounds to be fired for specific needs, versus having a single mode of operation, such as fully automatic, thereby conserving ammunition while maximizing on-target accuracy and effectiveness. This capability is most commonly found on assault rifles and military weapons of the 20th and 21st centuries. ==History== Early attempts at this technology were hindered by one or both of two obstacles, over-powerful ammunition and mechanical complexity. The latter led to excessive weight and unreliability in the firearm. One of the earliest designs dates to just before the turn of the 19th century with the development of the Cei-Rigotti, an early automatic rifle created by Italian Army officer Amerigo Cei-Rigotti that had selective-fire capability (single shots or burst). Another is the M1918 Browning Automatic Rifle (BAR) developed during the first World War. The BAR and its subsequent designs incorporated a variety of selective-fire functions. The first design (M1918) is a selective-fire, air-cooled automatic rifle that used a trigger mechanism with a fire selector lever that enabled operating in either semi-automatic or fully automatic firing modes. The selector lever is located on the left side of the receiver and is simultaneously the manual safety (selector lever in the "S" position – weapon is "safe", "F" – "Fire", "A" – "Automatic" fire).〔Ballou, James L., ''Rock in a Hard Place: The Browning Automatic Rifle'', Ontario, California: Collector Grade Publications Inc., ISBN 0-88935-263-1 (2000)〕 The next version (M1918A1) had a unique rate-of-fire reducer mechanism purchased from FN Herstal with two rates of automatic fire. This reducer mechanism was later changed to one designed by the Springfield Armory. The final version (M1918A2) provided two selectable rates of fully automatic fire only.〔 During World War II the Germans began development of the selective-fire function which resulted in the FG 42 battle rifle developed in 1942 at the request of the German Air Force (''Luftwaffe'') in 1941. Another German design that used selective fire was the StG 44 (abbreviation of Sturmgewehr 44 or "assault rifle 44") that was the first of its kind to see major deployment and is considered by many historians to be the first modern assault rifle.〔(ASSAULT RIFLES AND THEIR AMMUNITION: HISTORY AND PROSPECTS by Anthony G Williams )〕 "The principle of this weapon -- the reduction of muzzle impulse to get useful automatic fire within actual ranges of combat -- was probably the most important advance in small arms since the invention of smokeless powder."〔http://pogoarchives.org/labyrinth/09/02.pdf M16 Rifle Case Study. Prepared for the President's Blue Ribbon Defense Panel. March 16, 1970. By Richard R. Hallock, Colonel U.S. Army (Retired)〕 The selective-fire function was later seen in the Russian AK-47 (designed in 1946), the British EM-2 (designed in 1948), and the U.S. AR-15 (designed in 1957) and its variants. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「selective fire」の詳細全文を読む スポンサード リンク
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