Rifle · Proprietary
.338 Spectre
Subsonic wildcat designed for suppressed carbines; uses blown-out .30 Carbine brass to seat heavy .338 caliber projectiles for subsonic suppressed use..
- Caliber
- 0.338″ · 8.585 mm
- Introduced
- 2001
- Case
- Rimless
- Parent
- .30 Carbine
- Primary use
- Hunting
- Status
- Active
- Introduced
- 2001
- Type
- Rifle
- Origin
- United States
- Inventor
- Marty ter Weeme / Teppo Jutsu
- Manufacturer
- Marty ter Weeme / Teppo Jutsu
- Standard
- Proprietary
- Status
- Active
- Availability
- Uncommon
- Case capacity
- 26.5 gr H₂O
- Twist (typical)
- 1:10
- Primer
- Boxer Small Rifle
- Case type
- Rimless
- Max pressure
- 40,000 psi, SAAMI transducer
- Eff. range
- 150 yd
- Max range
- 3650 yd
- Recoil
- 6.5–7.3 ft·lb
- Subsonic
- Capable
Ballistics
Velocity only, no drag model: no published ballistic coefficient is on file for .338 Spectre, so this is the shape gravity alone gives the advertised velocity. Drag would steepen it. The tool below solves real loads through their published G1 or G7 model.
Open in Ballistic Compare- Parent case
- .30 Carbine
Representative trajectory — modeled from a single velocity input (no published BC for this cartridge yet).
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
SAAMI · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 8.59 | 0.338 | ~ |
| Neck ⌀ | 9.17 | 0.361 | ~ |
| Shoulder ⌀ | 10.24 | 0.403 | |
| Shoulder angle | 23° | — | |
| Base ⌀ | 10.80 | 0.425 | ~ |
| Rim ⌀ | 10.77 | 0.424 | ~ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.19 | 0.047 | |
| Neck length | 8.86 | 0.349 | |
| Case length | 31.50 | 1.240 | ~ |
| Overall length | 57.15 | 2.250 | ~ |
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. .338 Spectre is highlighted below.
Missing a dimension for .338 Spectre? 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.
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
Most-direct documented parent is 10mm Magnum (not yet in the reference).
Connected reference
History
Developed by Col. Jeff Cooper and John Ricco, the .338 Spectre is built from blown-out .30 Carbine brass to accommodate heavy .338 caliber bullets at subsonic velocities. Combined with a suppressor it provides effective terminal performance at close range from a compact carbine with minimal sound signature. It has seen use in some special operations testing.
FAQs
- What twist rate does .338 Spectre use?
- .338 Spectre typically uses a 1:10 twist rate.
- What bullet diameter is .338 Spectre?
- .338 Spectre uses a 0.338″ (8.585 mm) diameter bullet.
- Is .338 Spectre still in production?
- .338 Spectre is active; typical availability is uncommon.
- What is .338 Spectre used for?
- .338 Spectre is primarily used for hunting.
- What is .338 Spectre based on?
- .338 Spectre is derived from the .30 Carbine case.
Sources & provenance
- Secondary Cartridge Collector (cartridgecollector.net) — 338 Spectre · velocity, bullet ⌀, grain weights archived
- Secondary The Ballistic Assistant (theballisticassistant.com) — 338 Spectre: A Modern Subsonic Cartridge for the AR · bullet ⌀, velocity archived
Data & sources. Specs compiled from the Lindcott Armory reference; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
