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The Gyrojet is a family of unique firearms developed in the 1960s named for the method of gyroscopically stabilizing its projectiles. Rather than inert bullets, Gyrojets fire small rockets called Microjets which have little recoil and do not require a heavy barrel to resist the pressure of the combustion gases. Velocity on leaving the tube was very low, but increased to around at . The result is a very lightweight weapon.〔http://biskun.com/hobby/firearm/gyrojet.html 〕 Long out of production, today they are a coveted collector's item with prices for even the most common model ranging above $1,000. They are, however, rarely fired; ammunition, when available at all, can cost over $100 per round.〔(【引用サイトリンク】title=Svenska Vapensamlarföreningen, SVEVAP - Gyrojet )〕 == History == Robert Mainhardt and Art Biehl joined forces to form MBAssociates, or MBA, in order to develop Biehl's armor-piercing rocket rounds. Originally developed in a .51 caliber, the cartridges were self-contained self-propelled rockets with calibers ranging from .49 and 6mm to 20mm. A family of Gyrojet weapons was designed, including the pistol, the carbine and a rifle, as well as a proposed squad-level light machine gun and the Lancejet,〔(【引用サイトリンク】title=GyroJet Gallery Not For Sale )〕 however only the pistol and carbine were built. The space age-looking carbines and an assault rifle variant with a removable grip-inserted magazine were tested by the US Army, where they proved to have problems. One issue was that the vent ports allowed humid air into fuel, where it made the combustion considerably less reliable. The ports themselves could also become fouled fairly easily, although it was suggested that this could be solved by sealing the magazines or ports. Versions of the Gyrojet that were tested were inaccurate, cumbersome, slow loading, and unreliable (at best, a 1% failure rate was suggested; users quote worse figures, with many rounds that misfired the first time but later fired). Possibly these disadvantages could have been overcome in time, but the technology did not offer enough advantages over conventional small arms to survive. The original designer Robert Mainhardt enlisted the help of his friend Nick Minchakievich of Pleasanton, California, before 1962, in helping to stabilize the projectiles or ammunition. Minchakievich first developed retractable fins after rear ignition proved too dangerous. But the retractable fins proved too expensive, requiring advanced machining during production. The two experimental calibers with retractable fins were 6mm and 13mm. (Livermore Labs, p. 42.) Rushed for a solution due to the possibility of large government contracts, Minchakievich then quickly and ingeniously invented diagonal vented ports to make the projectiles or ammunition spin while advancing, thus relatively stabilize the projectiles using centrifugal force. This method was used in all the Mainhardt calibers for the Gyrojet. Minchakievich warned Mainhardt that rushing the project would only make the pistol shoddy and unreliable. Working for free out of his Livermore Aerospace Plastics Lab, Minchakievich requested six more months to perfect an accurate projectile, and make the Gyrojet more famous than the Colt Peacemaker. Mainhardt and the Air Force declined as current ordnance and technology was in demand for Vietnam. Minchakievich even attempted a marketing strategy by enlisting the help of Gene Roddenberry in using the pistol on Star Trek. Although Roddenberry loved the Gyrojet, he wanted a "ray gun" and not a pistol that merely shot a rocket projectile, no matter how advanced for the twentieth century. (Paramount Pictures, Correspondence, vol. XIX, p. 1309.) MBA projectiles are still found at building sites on Sycamore Creek Way and Happy Valley Road in Pleasanton where Minchakievich lived and did some experimentation. Nick Minchakievich also developed timed lighting in 1936 and radio controlled aircraft in 1938. His father Peter Minchakievich developed retractable storm windows in 1934 with patents US73734934A and US1983299. When spin stabilization was chosen for the Gyrojet, the compact electronics used in today's smart bullets were not available.〔(【引用サイトリンク】title=XM25 Rifle: Laser Guided Smart Bullets « DarkGovernment )〕 Both the cost and size of inertial navigation equipment have decreased greatly since a Gyrojet launcher was reviewed in ''Guns and Ammo Magazine'' in 1965.〔(【引用サイトリンク】title=GunsandAmmo )〕 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「Gyrojet」の詳細全文を読む スポンサード リンク
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