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.

The rifles use stocks and extraordinarily thick Krieger barrels bearing an 18 lb (8.2 kg) muzzle brake.

[1] Overall, depending on options, the rifles weigh from 85 to 120 pounds (39 to 54 kg) 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 ballistics of the .950 JDJ are more similar to that of the 20 mm autocannon round, which delivers approximately 39,500 foot-pounds force (53,600 joules).