Rifle · Not SAAMI standardized
.950 JDJ
The most powerful sporting rifle cartridge ever made.
- Caliber
- 0.95″ · 24.13 mm
- Introduced
- 2005
- Case
- Rebated
- Parent
- 20mm Vulcan
- Primary use
- Target, Anti-Materiel
- Status
- Active
- Introduced
- 2005
- Type
- Rifle
- Origin
- United States
- Inventor
- J.D. Jones / SSK Industries
- Manufacturer
- SSK Industries/Knight Rifles
- Standard
- Not SAAMI standardized
- Status
- Active
- Availability
- Rare
- Case capacity
- 441 gr H₂O
- Twist (typical)
- 1:24
- Primer
- .50 BMG primer
- Case type
- Rebated
- Max pressure
- 45,000 psi, SAAMI transducer
- Eff. range
- 1000 yd
- Max range
- 6850 yd
- Recoil
- 4,750.8–5,442.4 ft·lb
Ballistics
Published velocity/energy data isn't available for .950 JDJ. Parent case: 20mm Vulcan.
Performance
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
Wikipedia · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 24.13 | 0.950 | ~ |
| Neck ⌀ | 26.51 | 1.044 | |
| Shoulder ⌀ | 28.23 | 1.111 | |
| Shoulder angle | 30° | — | |
| Base ⌀ | 29.16 | 1.148 | ~ |
| Rim ⌀ | 26.92 | 1.060 | ~ |
| Belt ⌀ | n/a | ||
| Rim thickness | 2.73 | 0.107 | |
| Neck length | 24.91 | 0.981 | |
| Case length | 69.85 | 2.750 | ~ |
| Overall length | 101.60 | 4.000 | ~ |
Size vs familiar rounds
Drawn at true 1:1 — every case is accurate relative to the others. Absolute size depends on your screen's pixel density, so measuring one against a real ruler may be off. .950 JDJ is highlighted below.
Missing a dimension for .950 JDJ? Some case measurements aren't in a published SAAMI/CIP drawing yet. Have a factory or reamer print? Send it → — verified hard-to-find data earns a free Lindcott sticker.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Reloading costestimate cost per round vs factory
Estimate your cost per round and how it compares to factory. Inputs are yours — nothing is stored.
Cost estimate only — not load data. Charge weight is your input; follow published manuals for safe charges.
Lineage
History
Developed in 2005 by J.D. Jones of SSK Industries, the .950 JDJ is the world record holder for the most powerful commercially produced sporting rifle cartridge. Only a handful of rifles exist, all custom-built. The cartridge uses .50 BMG primers and custom-made brass. The cost per round is several hundred dollars. The rifles require NFA registration as Destructive Devices if the bore exceeds 0.5" (which it does), making ownership and use highly regulated.
FAQs
- What twist rate does .950 JDJ use?
- .950 JDJ typically uses a 1:24 twist rate.
- What bullet diameter is .950 JDJ?
- .950 JDJ uses a 0.95″ (24.13 mm) diameter bullet.
- Is .950 JDJ still in production?
- .950 JDJ is active; typical availability is rare.
- What is .950 JDJ used for?
- .950 JDJ is primarily used for target, anti-materiel.
- What is .950 JDJ based on?
- .950 JDJ is derived from the 20mm Vulcan case.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 6 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
