Rifle · SAAMI
.450 Bushmaster
SAAMI-standardized big-bore AR-15 cartridge.
- Caliber
- 0.4524″ · 11.49 mm
- Introduced
- 2007
- Case
- Rebated
- Parent
- .284 Winchester
- Primary use
- Hunting
- Status
- Active
- Introduced
- 2007
- Type
- Rifle
- Origin
- United States
- Inventor
- Tim LeGendre / Bushmaster
- Manufacturer
- Bushmaster / Hornady
- Standard
- SAAMI
- Status
- Active
- Availability
- Common
- Case capacity
- 59.5 gr H₂O
- Twist (typical)
- 1:24
- Primer
- Large Rifle
- Case type
- Rebated
- Max pressure
- 38,500 psi, SAAMI transducer
- Eff. range
- 250 yd
- Max range
- 2600 yd
- Recoil
- 20–25.3 ft·lb
Ballistics
Published velocity/energy data isn't available for .450 Bushmaster. Parent case: .284 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.
Lazzeroni/MAST drawing · verified| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 11.49 | 0.452 | ✓ |
| Neck ⌀ | 12.19 | 0.480 | ✓ |
| Shoulder ⌀ | n/a | ||
| Shoulder angle | n/a | ||
| Base ⌀ | 12.70 | 0.500 | ✓ |
| Rim ⌀ | 12.01 | 0.473 | ✓ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.37 | 0.054 | ✓ |
| Neck length | n/a | ||
| Case length | 43.18 | 1.700 | ✓ |
| Overall length | 57.40 | 2.260 | ✓ |
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. .450 Bushmaster is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Suitable powders
1 reloading powder listed for .450 Bushmaster, 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 .450 Bushmaster
Lineage
Connected reference
History
Originally developed by Tim LeGendre and licensed to Bushmaster in 2007. Commercialized with Hornady ammunition support. SAAMI standardization gave it advantage over proprietary competitors. Became very popular when several Midwestern states legalized straight-wall cartridges for deer hunting. Ohio, Indiana, and Michigan hunters embraced it. Most commercially successful of the AR-15 big-bore cartridges.
FAQs
- What twist rate does .450 Bushmaster use?
- .450 Bushmaster typically uses a 1:24 twist rate.
- What bullet diameter is .450 Bushmaster?
- .450 Bushmaster uses a 0.4524″ (11.49 mm) diameter bullet.
- Is .450 Bushmaster still in production?
- .450 Bushmaster is active; typical availability is common.
- What is .450 Bushmaster used for?
- .450 Bushmaster is primarily used for hunting.
- What is .450 Bushmaster based on?
- .450 Bushmaster is derived from the .284 Winchester case.
- What are the best powders for .450 Bushmaster?
- Reloading powders commonly listed for .450 Bushmaster include Lil'Gun.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 66 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
