CLOSED AND OPEN BOLT SYSTEMS

THIS 62 PAGE BOOKLET CONTAINES OVER 100 PHOTOS AND INCLUDES SEVERAL PAGES OF PATENTS / APPLICATIONS. ALL INCLUSIVE IS A HISTORY, CLASSIFICATION OF VARIOUS PATTERNS AND GENERAL SPECIFICATIONS.

THE AUTHOR

KIJIRO NAMBU

NAMBU MACHINE PISTOLS

THE AUTHOR

KIJIRO NAMBU

NAMBU MACHINE PISTOLS

ARTICLES

AIR CRAFT WEAPONS

From some 230 BIBLIOGRAPHICAL REFERENCES,

this literary work is composed of

542 PAGES with

686 ILLUSTRATIONS, including patent drawings and descriptions.

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THIS 62 PAGE BOOKLET CONTAINES OVER 100 PHOTOS AND INCLUDES SEVERAL PAGES OF PATENTS / APPLICATIONS. ALL INCLUSIVE IS A HISTORY, CLASSIFICATION OF VARIOUS PATTERNS AND GENERAL SPECIFICATIONS.

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DEFINITIONS
CLOSED AND OPEN BOLT SYSTEMS - DEFLECTION

CLOSED AND OPEN BOLT SYSTEMS
Although each system has purpose of function, the open bolt system was necessitated with automatic weapon development. In general the development of cartridge firearms utilized the closed bolt system.

The closed bolt system in automatic weapons provided that when firing is interrupted by release of the trigger [or sear in fixed weapons], it allows the bolt to close with a live cartridge in the barrel chamber ready for trigger/firing pin release. Depressing the trigger allows the firing of the cartridge.

For the open bolt system when releasing the trigger interrupts firing, the bolt is held in its rearward position with a fully open chamber. When trigger is depressed the bolt moves forward picking up, chambering and firing a live cartridge without additional manual function. The open bolt system was considered essential in automatic weapons to leave an open chamber and allow air circulation for cooling. This was beneficial in preventing “cook off” or premature firing of a chambered cartridge in an overheated barrel. The major disadvantage of the open chamber was foreign material could gather, especially in lubricated areas, and cause jams, malfunctions and parts breakage.

COAXIAL [MOUNTS]
The mounting of a secondary gun, usually small caliber, next to and in parallel with a larger caliber primary gun, both on a single axis, concentrically with both weapons aiming in the same direction. Tank turrets often utilize this combination and purposely use the small caliber gun as a target spotter.

CONVERSION FACTORS
To convert millimeters to inches, divide by 25.4
To convert centimeters to inches, divide by 2.54
To convert grams to grains, multiply by 15.432
To convert grams to ounces, divide by 28.35
To convert kilograms to pounds, multiply by 2.2

COOK OFF
The reference to preignition of a cartridge in the barrel chamber generally caused by high heat absorption from the barrel. It was a common problem in early automatic weapon design, especially those firing from closed bolt position whereby a live cartridge is held chambered in a hot barrel. Eventually innovations such as water cooling, air cooling and open bolt positioning reduced the problem, however sustained firing of certain automatic weapons for an extended period of time will produce “cook offs”.

DEFLECTION
The projected angle between the position of a moving target and the required aiming, point, [lead], to accomplish contact.