The .309 JDJ is a larger SSK JDJ cartridge based on the .444 Marlin case necked down to .30 caliber. It is one of the more capable TC Contender chamberings for large game, approaching .308 Winchester performance from a pistol barrel.
Type: Pistol
Introduced: 1979, USA
Parent case: .444 Marlin
Standardization: Proprietary
Bullet diameter: 0.308" (7.82 mm)
Case length: 1.56" (39.62 mm)
Overall length: 2.01" (51.05 mm)
Rim type: Rimmed
Primer: Large Pistol
Muzzle velocity: 1800–2200 fps
Muzzle energy: 1081–1934 ft-lbs
Effective range: 150 yd
Common bullet weights: 150, 165, 180 gr
Primary use: hunting, handgun_hunting
Production status: Active
Also known as: 309 JDJ · .30 JDJ
History: Developed by J.D. Jones in the late 1970s, the .309 JDJ is built on the .444 Marlin case to allow larger powder capacity than the smaller JDJ designs. It is a serious deer and hog cartridge in Contender or Encore pistol form.
Notable firearms: Thompson/Center Contender, TC Encore
Similar cartridges: .30-30 Winchester, .30 Herrett, .308 Winchester