Lindcott Armory Rifle · Obsolete
12.7x81mmSR Vickers
British heavy machine gun and aircraft cannon cartridge developed for the Vickers Class C heavy machine gun and later aircraft use.
- Caliber
- 0.5138″ · 13.05 mm
- Introduced
- 1925
- Case
- Semi-Rimmed
- Primary use
- Military, Anti-Materiel
- Status
- Discontinued
- Introduced
- 1925
- Type
- Rifle
- Origin
- United Kingdom
- Inventor
- Vickers / British military
- Manufacturer
- Kynoch
- Standard
- Obsolete
- Status
- Discontinued
- Availability
- Antique
- Case capacity
- 175 gr H₂O
- Twist (typical)
- 1:15
- Primer
- Berdan Large Rifle
- Case type
- Semi-Rimmed
- Max pressure
- 45,000 psi
- Eff. range
- 800 yd
- Max range
- 2500 yd
- Recoil
- 60–80 ft·lb
Ballistics
- Parent case
- —
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 ⌀ | 13.05 | 0.514 | · |
| Neck ⌀ | 13.80 | 0.543 | · |
| Shoulder ⌀ | 16.30 | 0.642 | ~ |
| Shoulder angle | 17.6° | — | ~ |
| Base ⌀ | 18.32 | 0.721 | · |
| Rim ⌀ | 19.55 | 0.770 | · |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.90 | 0.075 | ~ |
| Neck length | 14.00 | 0.551 | ≈ |
| Case length | 81.20 | 3.197 | · |
| Overall length | 107.20 | 4.220 | · |
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. 12.7x81mmSR Vickers is highlighted below.
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.
Connected reference
History
Developed in the early 1920s for a new class of British heavy machine guns, adopted as the Vickers .5 Class C gun. Used in RAF aircraft and on naval vessels through WWII. The semi-rimmed case allowed reliable feeding in both belt and drum feed systems. Replaced post-WWII by .50 BMG (12.7x99mm) as NATO standardization aligned British forces with American ammunition. Original ammunition is extremely scarce and of antique collector status only.
FAQs
- What twist rate does 12.7x81mmSR Vickers use?
- 12.7x81mmSR Vickers typically uses a 1:15 twist rate.
- What bullet diameter is 12.7x81mmSR Vickers?
- 12.7x81mmSR Vickers uses a 0.5138″ (13.05 mm) diameter bullet.
- Is 12.7x81mmSR Vickers still in production?
- 12.7x81mmSR Vickers is discontinued; typical availability is antique.
- What is 12.7x81mmSR Vickers used for?
- 12.7x81mmSR Vickers is primarily used for military, anti-materiel.
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 →