Author:?CaptianNemo? Source:http://ftr.wot-news.com/2014/10/31/t47-37mm-experimental-gun/

The T47 37mm Experimental Gun was provided by Division 1 through the Franklin Institute. The gun is essentially a modified 40mm Bofors gun (Navy Speciation) which fired a series of different projectiles using different primers and powders. Overall length was 88.58 inches.

T47 37毫米實(shí)驗(yàn)炮由第1師通過富蘭克林研究所提供。炮本質(zhì)上是一種改良的40毫米博福斯炮(海軍型號)，使用不同的底漆和發(fā)射藥發(fā)射一系列不同的彈藥。總長度為88.58英寸。

The barrel is chromium-plated and was made by boring a 40mm(Bofors) tube for 37mm and chambering it for a standard 40mm(Bofors) cartridge case necked down to accommodate a 37mm projectile. The first gun barrel was mounted on a standard 57mm carriage and then sent off to Aberdeen Proving Grounds for testing. A second gun barrel was shipped off to Division 1 , NDRC ballistic firing range at Carderock, Maryland for ballistic tests. The second barrel failed (on round number 51) after the chromium plating failed and it was determined that the plating was too thin and it notes in the report that it was recommended that another (third) barrel be produced with the correct chromium plating thickness. The report does not say if a third barrel was produced.

槍管是鍍鉻的，通過為37mm槍管鏜孔（boring）一根40mm博福斯炮管并將其裝進(jìn)一個(gè)標(biāo)準(zhǔn)的40mm博福斯彈殼內(nèi)以容納一枚37mm彈丸。第一炮管安裝在一個(gè)標(biāo)準(zhǔn)的57毫米炮架上，然后送到阿伯丁試驗(yàn)場進(jìn)行測試。第二個(gè)槍管被運(yùn)往馬里蘭州卡德洛克的國家發(fā)改委彈道射擊場第1師（Division 1 , NDRC ballistic firing range at Carderock, Maryland?）進(jìn)行彈道測試。在鍍鉻失敗后，第二根槍管在第51輪射擊測試時(shí)失敗了，并被確定為鍍層太薄，報(bào)告中指出建議生產(chǎn)另一個(gè)鍍鉻厚度正確的第三根槍管。報(bào)告沒有具體說明最后是否生產(chǎn)了第三根槍管。

The entire propose of the gun was to test pre-engraved projectiles combined with chrome plating the barrel which had been shown to extend the velocity life of the gun. The projectiles are made of Parco-Lubricated Steel which is where the surface of the projectile is treated with an Iron Phosphate coating.

該炮的全部建議是測試預(yù)先開槽的彈頭與鍍鉻的槍管相結(jié)合，這已被證明可以延長炮的速度壽命。彈丸由parco潤滑鋼制成，彈丸表面用磷酸鐵涂層處理。

The chamber volume was 31.43 cubic inches with a capacity of 29.9 cubic inches. The travel of the projectile from seating to ejection 73.96 inches(1878.584mm) another part of the source document lists projectile travel length as 76.58 inches(1945.13mm) which would produces a 50.77 calibers to 52.57 long barrel.

彈膛體積為31.43立方英寸，容量為29.9立方英寸。彈藥后座的行程為73.96英寸(1878.584mm)，源文件的另一部分列出了彈藥行程長度為76.58英寸(1945.13毫米)，這意味著將產(chǎn)生50.77口徑到52.57長的槍管。

For test purposes the Experimental T47 was tested with a range of 37mm projectile weights from 1.34lbs to 1.92lbs. Six different projectiles in all. Out of the 12 results posted 1 is 1.92lbs and 1 is 1.34lbs the majority is 1.62lbs.For the 37-mm projectiles the velocities range from 3,260(50% Service Charge) to 3,870(100% Service Charge) fps for projectiles weighing 1.92lbs to 1.34lb. The 1.62-lb pre-engraved projectile at the muzzle had the velocity of about 3,500 fps.

為了測試目的，實(shí)驗(yàn)T47在37mm彈丸重量范圍從1.34磅到1.92磅之間進(jìn)行了測試?？偣擦N不同的彈頭。在發(fā)布的12個(gè)結(jié)果中，1個(gè)是1.92磅，1個(gè)是1.34磅，大多數(shù)是1.62磅。對于重量為1.92磅至1.34磅的37毫米炮彈，其速度范圍為3,260 fps(50% Service Charge)至3,870 fps(100% Service Charge)。1.62磅預(yù)刻彈的炮口初速約為3,500 fps。

The six lands for the pre-engraved projectile had a constant twist of 24 calibers per turn. (1 turn in 24 calibers although another part of the same document gives this same info as 1 in 25).? The groves were 0.030 inches in depth with the lands pointed on a 30 degree slope at the origin of rifling and by changing the feed mechanism to prevent rotation of the previously indexed round.? The projectile in turn had six corresponding splines pointed with a 30 degree slope to match the lands.? The rounds were aligned in the case so that proper indexing of the case would automatically index the round.? The case was the standard 40mm(Bofors) case, necked to fit the 37mm pre-engraved projectile.? A guiding groove was cut in the base to guide the case on a vertical aligning track and an extension of this groove was cut in the edge of the flange to guide the case along a horizontal track in the tray.

這段說的啥看不懂不翻了

For the 37mm projectiles the observed values of deceleration range from 600 ft/sec2 to 1,250 ft/sec2 depending upon the service charge used, 50% and 100%. (The range is 500 ft long and is horizontal. Concrete piers for the support of velocity ‘solenoids’ are located at 50-ft intervals along the range.) The deceleration of 3-in. projectiles on the range has been computed for each successive trio of solenoids, and for the first arid the last pair of solenoids.

Maximum pressures in the 37mm gun ranged from 52 to 64 kilopounds psi.The two powders tested in the gun were M-1 powder (low flash-intensity) and M-5 powder (high flash-intensity). On several rounds pictures of the 37mrn projectiles in flight were made about 75 ft in front of the gun by illuminating the projectile with a “microflash”.

對于37mm彈丸，觀察到的減速值范圍從600 ft/sec2到1,250 ft/sec2，這取決于所使用的service?charge，50%和100%。(射程是水平的500英尺。用于支撐速度“螺線管”的混凝土橋墩位于沿著該范圍的50英尺間隔處。3-in的減速。射程上的彈丸已被計(jì)算為每個(gè)連續(xù)的三個(gè)螺線管，并為第一個(gè)和最后一對螺線管????。

37毫米炮的最大壓力范圍為52至64 kilopounds psi。槍中測試的兩種發(fā)射藥分別是M-1(低閃光強(qiáng)度)和M-5(高閃光強(qiáng)度)。在幾個(gè)回合中，37mm炮彈的飛行照片是在炮前約75英尺處用“微閃光”照亮炮彈拍攝的。

Armor penetration is not mentioned specifically but early on in the document a ‘current gun’ is mentioned, but not named, that penetrated a 3-5/8 inch plate of Class “B” Armor at 20 degrees incidence at a velocity of 3,440 fps. Which does fits the profile of the T47 gun. To be honest the anti-armor performance is not that great compared to the 37mm LJ and 37mm APDS. Both of which will be reserved for another time.

沒有特別提到穿甲性能，但在文件的早期提到了一門“current gun”，但沒有命名，它以20度射角以3440 fps的速度擊穿了一塊3-5/8英寸的B級裝甲。這符合T47火炮的概述。老實(shí)說，與37mmLJ和37毫米APDS相比，它的反裝甲性能并沒有那么好。這兩個(gè)都要留待以后再用。

Source of text and Photos:?Summary Technical Report of Division 1, NDRC. Volume 1 Hypervelocity Guns and the Control of Gun Erosion, January 1946.