Forgotten Cartridge 2 - .55 Boys
In First World War (1914-1918), the tank was developed by United Kingdom to clear the German trenches. In response to the problem, several ideas were has proposed. One of these ideas by using a large caliber rifle, fires the cartridge to penetrate the tank's armor, killing or wounding the tank crew, to stopping the tank. For this goal, German has developed 13.2x92 mm TuF cartridge, fires from Tankgewehr M1918 anti-tank rifle.
Although German was lost the war, the concept still influenced some European countries were developes a small arms cartridge for against light armor vehicle before Second World War (1939-1945). In 1930s, the United Kingdom starts to develop anti-tank rifle to counter enemy armor vehicle if the war started.
Captain H.C Boys, a designer of Royal Small Arms Factory, Enfield, have design a new cartridge by necked up .50 BMG(Browning Machine Gun, 12.7x99mm) to holding a larger projectile, hopes the armor penetration power would be enhanced. Furthermore, the belt also added on the cartridge case, prevents it accidentally chambered in .50 BMG firearms. The cartridge known as .55 Boys (13.9x99mmB). In 1937, it was adopted and produced with Boys Anti-Tank rifle.
Boys Anti-Tank rifle Mk. I
(Photo source: United States National Park Service, via Wikipedia)
However, the rifle was deemed to too weak for against the armor of the early Axis tank in late 1939 to 1940, the British still had to counting on the cartridge and those rifles for few years, since there no better options were available. In 1943, the anti-tank weapon - PIAT was issued, the PIATs' shaped charges proved to be more powerful than the rifle and its cartridge, they were phased out of service when PIAT became the British military's main infantries' anti-tank weapon.
PIAT (Projector, Infantry, Anti Tank) anti-tank laucher. (Photo source: Ranger Steve from Wikipedia)
Despite it was too weak for anti-tank purpose, the cartridge still was used around the WW2 in both the Pacific and Atlantic theaters. Such as
It also used by Finland, especially their Swedish volunteer during the Winter War and Continuation War. The cartridge was not adopted by any countries after the war.
It is my first belted cartridge 3D model ever made. Since there is no any other countries adopted it today, also, it was not for sport shooting purpose. Therefore, there none of any standard organizations, such as C.I.P or SAAMI for to assess the cartridge, including measuring the physical dimensions and publish the technical drawings with all dimensions.
I have to find the original technical drawing from the internet. These drawings with diameter and length of different parts of the cartridge. However, just like most of technical drawings, no depth of rim recess, angle of the rim and case base angle was indicated. It known that was modified from .50 BMG. So, just refering the depth of rim recess, rim angle and case base angle of .50 BMG, and the problems solved.
The headstamp of the cartridge model, it was refer to actual photo from internet.
More new items will coming soon. Stay tune! :)
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