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Rifle · Proprietary

.505 Gibbs

Also known as .505 Magnum Rimless · 12.7x70mm

Massive British dangerous game cartridge.

Caliber
0.5051″ · 12.83 mm
Introduced
1911
Case
Rimless
Primary use
Hunting
Status
Limited

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VelocityBeing verified
EnergyBeing verified
Typical grains525 · 570 gr
Identity
Introduced
1911
Type
Rifle
Origin
United Kingdom
Inventor
George Gibbs
Manufacturer
George Gibbs
Standard
Proprietary
Status
Limited
Availability
Scarce
Build
Case capacity
178 gr H₂O
Twist (typical)
1:16
Primer
Large Rifle Magnum
Case type
Rimless
Pressure & range
Max pressure
39,160 psi, CIP transducer
Eff. range
150 yd
Max range
4900 yd
Recoil
75–100 ft·lb

Ballistics

Published velocity/energy data isn't available for .505 Gibbs.

Performance

Best for Withheld until verified
Best for Withheld until verified
Dimensionscase measurements · scale drawing · size vs familiar rounds

Case dimensions — the scale drawing at the top of the page is built from these.

CIP TDCC · verified
Measuremmin✓
Bullet ⌀ 12.830.505 ✓
Neck ⌀ 13.670.538 ✓
Shoulder ⌀ 15.240.600 ✓
Shoulder angle 37.6°— ✓
Base ⌀ 16.260.640 ✓
Rim ⌀ 16.260.640 ✓
Belt ⌀ n/a
Rim thickness 1.650.065 ✓
Neck length 16.560.652 ≈
Case length 80.013.150 ✓
Overall length 97.793.850 ✓

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. .505 Gibbs is highlighted below.

Factory loads

Verification

Being verified

Advertised FPS, energy, and BC are withheld until loads clear verification.

Suitable powders

3 reloading powders listed for .505 Gibbs, fastest to slowest. Cross-reference in the finder →

Norma 201Reloader 25Reloader 33
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.

Firearms chambered in .505 Gibbs

John Rigby & Co. Big Game .505 Gibbs 24-inchJohn Rigby & Co. Big Game .450 Rigby 24-inchJohn Rigby & Co. Big Game .375 H&H 24-inchChapuis Armes Progress R .416 Rigby 22-inchKimber Caprivi .416 RigbyKimber Caprivi .375 H&HMontana Rifle Company Professional Hunter .375 H&H MagMauser M98 Magnum .505 GibbsDakota Arms Dakota 76 .505 Gibbs 25-inchCZ CZ 550 Safari MagnumHeym SR30 .505 GibbsHolland & Holland Magazine Rifle .416 Rigby 24-inch

Lineage

Immediate parent
Root — no documented parent
Direct descendants (1 · 4 total)
.400 Taylor Magnum
Family TreeOpen .505 Gibbs in the interactive cartridge family tree

Connected reference

Reloading3 suitable powders — cross-reference

History

Introduced in 1911 by British gunmaker George Gibbs as the ultimate stopping rifle for dangerous game. Designed for close-range encounters with elephant, rhino, and buffalo in thick bush. The huge 500-600 grain bullets at moderate velocity provide incredible penetration and shocking power. Extremely limited production and use even in its heyday. True collector's cartridge today.

FAQs

What twist rate does .505 Gibbs use?
.505 Gibbs typically uses a 1:16 twist rate.
What bullet diameter is .505 Gibbs?
.505 Gibbs uses a 0.5051″ (12.83 mm) diameter bullet.
Is .505 Gibbs still in production?
.505 Gibbs is limited; typical availability is scarce.
What is .505 Gibbs used for?
.505 Gibbs is primarily used for hunting.
What are the best powders for .505 Gibbs?
Reloading powders commonly listed for .505 Gibbs include Norma 201, Reloader 25, Reloader 33.

Sources & provenance

Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 18 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →

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