Rifle · SAAMI
.243 Winchester
Dual-purpose cartridge.
- Caliber
- 0.243″ · 6.172 mm
- Introduced
- 1955
- Case
- Rimless
- Parent
- .308 Winchester
- Primary use
- Varmint, Hunting
- Status
- Active
- Introduced
- 1955
- Type
- Rifle
- Origin
- United States
- Inventor
- Winchester
- Manufacturer
- Winchester Ammunition
- Standard
- SAAMI
- Status
- Active
- Availability
- Abundant
- Case capacity
- 54.8 gr H₂O
- Twist (typical)
- 1:10
- Primer
- Large Rifle
- Case type
- Rimless
- Max pressure
- 60,000 psi, SAAMI transducer
- Eff. range
- 400 yd
- Max range
- 4600 yd
- Recoil
- 8–12 ft·lb
Introduced by Winchester Ammunition
Ballistics
Published velocity/energy data isn't available for .243 Winchester. Parent case: .308 Winchester.
Performance
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| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 6.17 | 0.243 | ✓ |
| Neck ⌀ | 7.01 | 0.276 | ✓ |
| Shoulder ⌀ | 11.53 | 0.454 | ✓ |
| Shoulder angle | 20° | — | ✓ |
| Base ⌀ | 11.96 | 0.471 | ✓ |
| Rim ⌀ | 12.01 | 0.473 | ✓ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.37 | 0.054 | ✓ |
| Neck length | 6.11 | 0.241 | ≈ |
| Case length | 51.94 | 2.045 | ✓ |
| Overall length | 68.83 | 2.710 | ✓ |
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. .243 Winchester is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Suitable powders
37 reloading powders listed for .243 Winchester, fastest to slowest. Cross-reference in the finder →
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 .243 Winchester
Lineage
Connected reference
History
Introduced by Winchester in 1955. Instantly popular as combination varmint/deer rifle. Considered the minimum for ethical deer hunting in many states.
FAQs
- What twist rate does .243 Winchester use?
- .243 Winchester typically uses a 1:10 twist rate.
- What bullet diameter is .243 Winchester?
- .243 Winchester uses a 0.243″ (6.172 mm) diameter bullet.
- Is .243 Winchester still in production?
- .243 Winchester is active; typical availability is abundant.
- What is .243 Winchester used for?
- .243 Winchester is primarily used for varmint, hunting.
- What is .243 Winchester based on?
- .243 Winchester is derived from the .308 Winchester case.
- What are the best powders for .243 Winchester?
- Reloading powders commonly listed for .243 Winchester include N530, Accurate 2520, RS52, Norma 201, among 37 suitable options.
Sources & provenance
- Standard C.I.P. — C.I.P. TDCC — Tables of Dimensions of Cartridges and Chambers
- Standard SAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawings archived
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 182 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
