重機槍
Heavy machine gun

context: zh_tw: 現代定義的重機槍（.50 或 12.7 毫米）的始祖是由約翰・摩西・勃朗寧製造的 M2 勃朗寧機槍，這類機槍在破壞力和移動能力上相對於老式重機槍有了提高，並且被裝備在車輛載具，飛機，建築物和輕型工事內。在這裡，“重機槍” 中的 “重” 字是來體現重機槍的威力和控制範圍。在第二次世界大戰期間，美軍在車輛載具，飛機和防禦工事中廣泛使用 M2 機槍。同樣的，蘇聯也在廣泛使用 DShK 重機槍。德軍的 MG34 及 MG42 兩款機槍大規模的出現在歐洲戰場，雖然他對步兵的攻擊十分有效，但其缺乏像 M2 那樣的反工事和反車輛的能力，這個弱點也在 D 日攻擊以後的戰役中體現了出來。現在，M2 重型機槍是美軍現役中服役時間最長的武器，並且該型機槍還在世界各國的軍隊中使用。目前，口徑小於 10 毫米一般被認為是中型機槍，而那些等於或大於 20 毫米一般被稱為機炮，而不是重機槍。
en: The modern definition refers to a class of large-caliber (generally .50 or 12.7mm) machine guns, pioneered by John Moses Browning with the M2 machine gun.  These weapons are designed to provide increased range, penetration and destructive power against vehicles, buildings, aircraft and light fortifications beyond the standard rifle calibers used in medium or general-purpose machine gun, or the intermediate cartridges used in light machine guns. In this sense, the "heavy" aspect of the weapon refers to its superior power and range over light- and medium-caliber weapons, in addition to its weight. This class of machine gun came into widespread use during World War II, when the M2 was used widely in fortifications, on vehicles and in aircraft by American forces. A similar HMG capacity was later fielded by the Soviets in the form of Vasily Degtyaryov's DShK in 12.7×108mm. The ubiquitous German MG42 general-purpose machine gun, though well-suited against infantry, lacked the M2's anti-fortification and anti-vehicle capability, a fact that was noted and lamented by the Germans. The continued need for a longer-range machine gun with anti-materiel capability to bridge the gap between exclusively anti-infantry weapons and exclusively anti-materiel weapons has led to the widespread adoption and modernization of the class, and most nations' armed forces are equipped with some type of HMG.
qas: question: zh_tw: 什麼時候開始使用 M2 輕機槍？
en: When did light machine M2 guns come to use?
answers: zh_tw: text: 第二次世界大戰
en: text: World War II,

context: zh_tw: 在十九世紀末期，加特林機槍等一些類似於努登費爾特槍之類的多管槍械的槍管口徑一般在 0.5 英寸到 1 英寸左右。但是這類武器的槍管易於發熱且過於笨重。馬克沁在製造設計他的單管反衝動力槍械時，其第一個設計只有 26 磅（11.8 公斤），可以發射 0.45 英寸槍彈（槍管口徑 24 英寸）。一張著名照片可以證明最初設計的機槍重量的確很輕：馬克沁本人只用一隻膀子就將他的重機槍連同著 15 磅（6.8 公斤）的三腳架一同拿起。這種武器，類似與現代的中型機槍，但是他不能進行長時間射擊而被拋棄。所以隨後，馬克沁發明了水冷套冷卻系統，使之能夠長時間射擊而不至槍管損壞，他也為其增加了更大的彈匣。這些改動也使得他的機槍增加了一定的重量。
en: When Maxim developed his recoil-powered machine gun using a single barrel, his first main design weighed a modest 26 pounds (11.8 kg) and fired a .45-inch rifle-caliber bullet from a 24-inch barrel. A famous photo of Maxim showed him picking it up by its 15-pound tripod (6.8 kg) with one arm. It was similar to present-day medium machine guns, but it could not be fired for extended periods due to overheating. As a result, Maxim created a water jacket cooling system to enable it to fire for extended periods. However, this added significant weight, as did the change to more powerful rifle cartridges.
qas: question: zh_tw: 步槍的水冷卻系統的缺陷是什麼？
en: The water cooling system for rifles had a design flaw, what was it?
answers: zh_tw: text: 增加了一定的重量
en: text: added significant weight

context: zh_tw: 在那個時代，有兩種重型連發武器，一種是手動轉輪式機槍，另一種是馬克沁水冷式機槍。很快，隨著時間的推移，越來越多的發明被使用在重機槍上，其中包括氣流裝置，反衝系統和聯動裝置（柯爾特 1895 型，Hotchkiss 等）。與此同時，設計者們拋開了笨重的水冷套，而是用其他的冷卻方式來代替他們，這些設計使用了諸如散熱片，散熱器等方法來改善槍管的散熱問題。重型的水冷機槍在第二次世界大戰到 1960 年代還在使用，但逐漸的，這類設計被更先進的風冷設計給淘汰了。因為靜置的機槍在戰場上不能充分的發揚他的火力，所以在使用重機槍的同時，人們還使用可摺疊的三腳架和二腳架來代替笨重的支架來支撐他，而且輕巧的風冷設計也使得重機槍在戰場上靈活的運動成為了可能。與此同時，在二戰期間，一些國家例如蘇聯，設計了口徑更大的重機槍（例如有大口徑的維克斯重機槍）。
en: There were thus two main types of heavy, rapid-fire weapons: the manually powered, multiple-barrel machine guns and the single-barrel Maxim guns. By the end of the 19th century, many new designs such as the M1895 Colt–Browning and Hotchkiss were developed, powered by gas operation or recoil operation.  Also, rather than the heavy water jacket, new designs introduced other types of barrel cooling, such as barrel replacement, metal fins, heat sinks or some combination of these.
qas: question: zh_tw: 有哪些不同型別的桶冷卻？
en: What different types of barrel cooling are there?
answers: zh_tw: text: 散熱片，散熱器
en: text: barrel replacement, metal fins, heat sinks