Rifle · Not SAAMI standardized · Not standardizedObsolete
12.7x55mm
12.7x55mm is a rimless bottlenecked rifle cartridge of Russia origin.
- Caliber
- 0.5122″ · 13.01 mm
- Introduced
- 2002
- Case
- Rimless
- Parent
- .338 Lapua Magnum
- Primary use
- Hunting
- Status
- Discontinued
- Obsolete
- Obsolete
- Introduced
- 2002
- Type
- Rifle
- Origin
- Russia
- Inventor
- Barnaul Cartridge Plant (approx: maker of record)
- Manufacturer
- Barnaul
- Standard
- Not SAAMI standardized · Not standardized
- SAAMI
- Not SAAMI standardized
- Obsolete
- Obsolete
- Status
- Discontinued
- Availability
- Rare
- Case capacity
- 98 gr H₂O
- Twist (typical)
- 1:20
- Primer
- Large Rifle
- Case type
- Rimless
- Max pressure
- 61,000 psi, CIP transducer
- Eff. range
- 150 yd
- Max range
- 750 yd
- Recoil
- 18.3–18.9 ft·lb
- Subsonic
- Capable
Introduced by Barnaul
Ballistics
Velocity only, no drag model: no published ballistic coefficient is on file for 12.7x55mm, 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
- .338 Lapua Magnum
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.
Wikipedia · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 13.01 | 0.512 | · |
| Neck ⌀ | 13.61 | 0.536 | |
| Shoulder ⌀ | 13.76 | 0.542 | · |
| Shoulder angle | 23° | — | |
| Base ⌀ | 14.86 | 0.585 | · |
| Rim ⌀ | 14.91 | 0.587 | |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.52 | 0.060 | |
| Neck length | 11.63 | 0.458 | |
| Case length | 54.91 | 2.162 | · |
| Overall length | 97.30 | 3.831 | · |
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. 12.7x55mm is highlighted below.
Missing a dimension for 12.7x55mm? 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
Connected reference
History
Introduced around 2002, derived from the .338 Lapua Magnum.
FAQs
- What twist rate does 12.7x55mm use?
- 12.7x55mm typically uses a 1:20 twist rate.
- What bullet diameter is 12.7x55mm?
- 12.7x55mm uses a 0.5122″ (13.01 mm) diameter bullet.
- Is 12.7x55mm still in production?
- 12.7x55mm is discontinued; typical availability is rare.
- What is 12.7x55mm used for?
- 12.7x55mm is primarily used for hunting.
- What is 12.7x55mm based on?
- 12.7x55mm is derived from the .338 Lapua Magnum case.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
