.950 JDJ
The .950 JDJ is a large caliber rifle cartridge developed by J. D. Jones
J. D. Jones
J. D. Jones is a firearms and cartridge designer, and president of SSK Industries. Jones began hunting at an early age, and became interested in bullet casting and handloading firearms cartridges...

 of SSK Industries. Jones is also the noted developer of many other well-known cartridges, such as the Whisper family
Whisper Family of Firearm Cartridges
The Whisper family of firearm cartridges is a group of wildcat cartridges developed in the early 1990s by J.D. Jones of SSK Industries. The Whisper Family was developed as a line of accurate, multi-purpose cartridges using relatively heavy rifle bullets for a given caliber in subsonic loads...



The .950 JDJ is the world's largest, and most powerful caliber rifle cartridge. Loaded .950 JDJ cartridges are approximately the length of an empty .50 BMG
.50 BMG
The .50 Browning Machine Gun or 12.7×99mm NATO is a cartridge developed for the Browning .50 caliber machine gun in the late 1910s. Entering service officially in 1921, the round is based on a greatly scaled-up .30-06 cartridge...

 casing (i.e., 4"), and are based on a 20x102mm
20 mm caliber
The 20 mm caliber is a specific size of cannon or autocannon ammunition, commonly the smallest caliber which is unambiguously a cannon and not a heavy machine gun....

 case shortened and necked up to accept the .950" bullet. Projectiles are custom-made and most commonly weigh 3600 gr which is 8.2 ounces or over half a pound.


As its name implies, rifles chambered for the cartridge have a bore diameter of 0.950", which would normally classify them as Destructive Devices under the 1968 (1934) National Firearms Act
National Firearms Act
The National Firearms Act , 73rd Congress, Sess. 2, ch. 757, , enacted on June 26, 1934, currently codified as amended as , is an Act of Congress that, in general, imposes a statutory excise tax on the manufacture and transfer of certain firearms and mandates the registration of those firearms. The...

. However, SSK sought and received a "Sporting Use Exception" to de-regulate the rifles, meaning they can be purchased like any other Title I rifle by a person over age 18 with no felonious criminal record. The rifles themselves, of which only a handful have been made, use McMillan stocks and extraordinarily thick Krieger barrels bearing an 18 lb (8.2 kg) muzzle brake. Overall, depending on options, the rifles weigh from 80 to 110 lb (36.3 to 49.9 ) and are therefore only useful for shooting from a bench rest or heavy bipod. Despite the weight, recoil is significant, and shooters must be sure to choose components (i.e., scopes
Telescopic sight
A telescopic sight, commonly called a scope, is a sighting device that is based on an optical refracting telescope. They are equipped with some form of graphic image pattern mounted in an optically appropriate position in their optical system to give an accurate aiming point...

 and bipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...

s) that can handle the abuse. The sheer size and weight of these weapons makes them impractical for hunting use, as they cannot be carried afield. Thus, they are largely "range queens"—rifles that are brought to the range for a fun time, but not usually used for hunting or other "more practical" uses. Additionally, the cost of owning and operating such a firearm is beyond most shooters; the rifles cost ~US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

8,000, loaded cartridges are $40 each, and the individual lathe-turned bronze
Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

 bullets are $10 apiece.


The cartridge propels its 3600 gr bullet at approximately 2200 ft/s (670.6 m/s). This yields a muzzle energy of 38685 ft.lbf and a momentum of 154.1 Newton-seconds. This kinetic energy would allow the .950 JDJ to pass through several body-armored humans. It is comparable to the original tank rounds of World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 in terms of ballistic energy.

By comparison, the 5.56x45 cartridge, used in the M16 rifle
M16 rifle
The M16 is the United States military designation for the AR-15 rifle adapted for both semi-automatic and full-automatic fire. Colt purchased the rights to the AR-15 from ArmaLite, and currently uses that designation only for semi-automatic versions of the rifle. The M16 fires the 5.56×45mm NATO...

, produces between 1200 ft.lbf, while the .308 Winchester
.308 Winchester
The .308 Winchester is a rifle cartridge and is the commercial cartridge upon which the military 7.62x51mm NATO centerfire cartridge is based. The .308 Winchester was introduced in 1952, two years prior to the NATO adoption of the 7.62x51mm NATO T65...

, a favorite for hunters and medium-range police/military sniping, produces between 2000 ft.lbf depending on the load used. The ballistics of the .950 JDJ is more similar to that of the 20mm autocannon round, which delivers approximately 39500 ft.lbf. The muzzle energy of the .950 JDJ is comparable to the kinetic energy of a 2800 lb (1,270.1 kg) automobile traveling at 20 mile per hour.

In a 110 lb (49.9 kg) rifle, this will develop well over 200 ft.lbf of free recoil energy if an efficient muzzle brake is not used. This is far beyond the shoulder-firing capacity of nearly all humans, even without considering the difficulty of shouldering such a heavy rifle. Shooting is usually heavy "lead sled" or similar shooting rest, and the rifle is not held to the shoulder because of the severe recoil and possible injury. The rifle scope has significant eye relief to avoid injuring the ocular orbit.
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