Rifle · SAAMI
.280 Ackley Improved
Improved .280 Remington with more powder capacity.
- Caliber
- 0.284″ · 7.214 mm
- Introduced
- 1960
- Case
- Rimless
- Parent
- .280 Remington
- Primary use
- Hunting, Target
- Status
- Active
- Introduced
- 1960
- Type
- Rifle
- Origin
- United States
- Inventor
- P.O. Ackley
- Manufacturer
- Nosler (commercial)
- Standard
- SAAMI
- Status
- Active
- Availability
- Moderate
- Case capacity
- 73.1 gr H₂O
- Twist (typical)
- 1:9
- Primer
- Large Rifle
- Case type
- Rimless
- Max pressure
- 65,000 psi, SAAMI transducer
- Eff. range
- 600 yd
- Max range
- 6350 yd
- Recoil
- 18–25.5 ft·lb
Ballistics
Published velocity/energy data isn't available for .280 Ackley Improved. Parent case: .280 Remington.
Performance
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
SAAMI · verified| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 7.21 | 0.284 | ✓ |
| Neck ⌀ | 8.00 | 0.315 | ✓ |
| Shoulder ⌀ | 11.53 | 0.454 | ✓ |
| Shoulder angle | 40° | — | ✓ |
| Base ⌀ | 11.90 | 0.469 | ✓ |
| Rim ⌀ | 11.99 | 0.472 | ✓ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.19 | 0.047 | ~ |
| Neck length | 8.78 | 0.346 | ≈ |
| Case length | 64.14 | 2.525 | ✓ |
| Overall length | 84.58 | 3.330 | ✓ |
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. .280 Ackley Improved is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Suitable powders
2 reloading powders listed for .280 Ackley Improved, 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 .280 Ackley Improved
Lineage
Connected reference
History
Created by legendary wildcatter P.O. Ackley by fire-forming .280 Remington brass to 40-degree shoulder with less body taper. Increases powder capacity by ~6%. Wildcat for 45+ years until Nosler commercialized it in 2007 and achieved SAAMI standardization. Provides 7mm Rem Mag ballistics with standard-length action and less powder. Growing in popularity.
FAQs
- What twist rate does .280 Ackley Improved use?
- .280 Ackley Improved typically uses a 1:9 twist rate.
- What bullet diameter is .280 Ackley Improved?
- .280 Ackley Improved uses a 0.284″ (7.214 mm) diameter bullet.
- Is .280 Ackley Improved still in production?
- .280 Ackley Improved is active; typical availability is moderate.
- What is .280 Ackley Improved used for?
- .280 Ackley Improved is primarily used for hunting, target.
- What is .280 Ackley Improved based on?
- .280 Ackley Improved is derived from the .280 Remington case.
- What are the best powders for .280 Ackley Improved?
- Reloading powders commonly listed for .280 Ackley Improved include Reloader 17, Reloader 19.
Sources & provenance
- Standard SAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawings archived
- Manufacturer Hornady — Hornady Ballistic Coefficient tables (ELD-VT) · representative_gun, grain_ballistics archived
- Manufacturer Nosler — 7mm 140gr AccuBond (50ct) — bullet specifications · grain_ballistics, representative_gun archived
- Manufacturer Nosler — 280 Ackley Improved 160gr AccuBond Trophy Grade Ammunition (Part #60076) · grain_ballistics, representative_gun archived
- Manufacturer Federal Premium — Terminal Ascent 280 Ackley Improved 155 Grain (P280AITA1) · grain_ballistics, representative_gun archived
- Manufacturer Federal Premium — Terminal Ascent Component Bullet .284 155 Grain (PB284TA1) · representative_gun, grain_ballistics archived
- Manufacturer Hornady — 280 Ackley 162 gr ELD-X Precision Hunter (Item #85586) · representative_gun, grain_ballistics archived
- Manufacturer Nosler — 7mm 160gr AccuBond (50ct) — bullet specifications · grain_ballistics, representative_gun archived
- Manufacturer Nosler — 280 Ackley Improved 140gr AccuBond Trophy Grade Ammunition (Part #60043) · grain_ballistics, representative_gun archived
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 35 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
