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The Jarmann M1884 is a Norwegian bolt action repeating rifle designed in 1878 adopted in 1884. The Jarmann is the first centerfire, repeating bolt-action rifle, adopted as standard issue based on an entirely new design. Earlier rifles like the Swiss Vetterli used rimfire cartridges, the Winchester Hotchkiss and early models of the Remington Lee saw only limited military use, the German Mauser Model 71/84 and early Kropatschek rifles were based on earlier designs. The Jarmann's adoption, and subsequent modifications, turned the Norwegian Army from a fighting force armed with single-shot black-powder weapons into a force armed with modern repeating weapons firing smokeless ammunition. Several thousand were manufactured to equip both Norwegian and Swedish forces in the 1880s. The design is unique, and was the brainchild of Norwegian engineer Jacob Smith Jarmann. After the design had been phased out of the Norwegian Army, a number of the weapons were rebuilt as harpoon guns. ==Description== The Jarmann M1884 fired a 10.15 mm black powder cartridge in an 8-round, tubular magazine in which the rounds were lined up in a tube below the barrel. It has a non-rotating bolt (the part of the action that seals the rear end of the barrel) locked by a rotating bolt handle, and reputedly a smooth action. However, this action is not considered strong enough to fire modern ammunition, since the only locking is provided by the rotating bolt handle. Jacob Smith Jarmann designed his first breech-loading rifle—firing cardboard cartridges—in 1838, but this was turned down by the armed forces at the time. The logic was that a rifle capable of firing 13 shots a minute would be impossible to resupply with enough ammunition. In the 1870s, he stepped down from the daily running of his workshop to work on his newly invented bolt-action rifle. According to the patent, three particulars were considered new and unique with the action he had developed:〔 *The extractor, which not only pulled the spent round out of the breech, but also served to limit the bolt's rearward motion. *The design of the rotating bolt handle, which served to lock the bolt to the receiver in the forward position. *The way the extractor was secured to the body of the bolt. Another interesting oddity is that the Jarmann action does not have a separate ejector, but instead relies on the fact that the extractor pushes the spent round down onto the elevator. The resulting friction was enough to safely eject the round from the receiver. The design was first tested by a joint Norwegian-Swedish rifle commission. Their first tests were favorable but highlighted the desirability of a repeating weapon, that is, a weapon with a magazine. Several magazine-fed prototype rifles were built—Ole Herman Johannes Krag, the designer of the Krag–Petersson and the Krag–Jørgensen repeating rifles, designed two different magazines〔 for the Jarmann rifle: one virtually identical to the magazine used on the Krag–Petersson, one which was the forerunner for the magazine he used on the Krag–Jørgensen. Jacob Smith Jarmann himself also made several prototypes,〔 mainly with tubular magazines under the barrel or detachable magazines mounted sideways over the bolt. The latter was considered unusable in the field, and in the end a tubular magazine was selected for the weapon. The magazine is similar to the Kropatschek〔(【引用サイトリンク】 url = http://www.gunsworld.com/world/kropatch_us.htm )〕 tubular magazine and may have been inspired by it, although it is just as possible that the magazine is inspired by the Krag–Petersson magazine. Despite being a trailblazer with its then-pioneering design, the Jarmann M1884 cannot be considered successful. The combination of tubular magazine and centerfire ammunition has been referred to as "too excitable", especially when used with pointed bullets.〔 Also, the balance of the weapon changed with every shot fired. However, both of these issues are common to all firearms that use tubular magazines. The first Jarmann design was firmly a single-shot weapon, and Jacob Smith Jarmann was reportedly at first unwilling〔 to design a magazine for it. This may explain why the magazine and bolt do not always work well together. The sights on the Jarmann M1884, as first issued,〔 were graduated from 200 m to 1600 m. There was an additional sidemounted volley sight, intended for indirect volley fire over long distances, from 1600 m to 2400 m. To be effective, an entire company would have to fire at the same time, which would ensure that at least some of the bullets found their targets. During production, the sights were modified, and M1884s with serial numbers higher than 4330 also had a battle sight fitted to the backside of the sight leaf,〔 which could be revealed by folding the leaf fully forward. The battle sight was set to a fixed range of about 430 m (470 yd), close to the maximum point-blank range of the weapon. During testing to determine the correct graduation of the sights the rifle commission used improved ammunition, which increased the muzzle velocity to about 485 to 500 m/s.〔 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「Jarmann M1884」の詳細全文を読む スポンサード リンク
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