| .950 JDJ | |
| Origin: | United States |
| Type: | Rifle |
| Designer: | J. D. Jones |
| Manufacturer: | SSK Industries/Knight Rifles |
| Parent: | 20×110mm Hispano |
| Bullet: | 0.95inches |
| Case Length: | 2.75inches |
| Bw1: | 3600 |
| Vel1: | 2200 |
| En1: | 38685 |
The .950 JDJ (24.1×70mm) is a powerful large caliber rifle cartridge developed by American gunsmith and weapon designer J. D. Jones of SSK Industries.
.950 JDJ cases are approximately 70 mm in length, and are based on a 20×110mm case shortened and necked up to accept the 0.95inches bullet. Projectiles are custom-made and most commonly weigh which is 8.2 ounces or over half a pound.
As its name implies, rifles chambered for the cartridge have a groove diameter of 0.95inches. SSK received a "Sporting Use Exception" to de-regulate the rifles. Thus, in the United States, they can be owned like any other Title I rifle by an American citizen at age 18. The rifles use stocks and extraordinarily thick Krieger barrels bearing an 18lb muzzle brake.[1] Overall, depending on options, the rifles weigh from 85to and are therefore only useful for shooting from a bench rest or heavy bipod.[2] Despite the weight, recoil is significant and shooters must be sure to choose components (i.e., scopes and bipods) that can handle the force. The sheer size, weight, and power of these rifles make them rather impractical for hunting use. SSK only manufactured three of these rifles and as of 2014 no longer produces the ammunition.[1] [3]
The cartridge propels its 3600gr bullet at approximately 2200ft/s.[1] This yields a muzzle energy of 386850NaN0.[4]
By comparison, the 5.56×45mm NATO cartridge, used in the M16 and M4 rifles, produces between 1200-, while the .308 Winchester, a favorite for hunters, police, and military snipers, produces between 2000- depending on the load used. Even the .50 BMG, which has a kinetic energy of around 13000- delivers less than half the energy. The ballistics of the .950 JDJ are more similar to that of the 20 mm autocannon round, which delivers approximately 39500ft.lbf. The muzzle energy of the .950 JDJ is comparable to the kinetic energy of a 2800lb automobile traveling at 20mph.
In a 110lb rifle, this will develop well over 200ft.lbf of free recoil energy. Shooting usually involves a heavy "lead sled" or similar shooting rest, and the rifle scope has significant eye relief to avoid injuring the ocular orbit.