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Lindcott Armory

Rifle · SAAMI

.450 Bushmaster

Also known as .450 BM · 11.5x43mm

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

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VelocityBeing verified
EnergyBeing verified
Typical grains250 · 260 · 300 gr
Identity
Introduced
2007
Type
Rifle
Origin
United States
Inventor
Tim LeGendre / Bushmaster
Manufacturer
Bushmaster / Hornady
Standard
SAAMI
Status
Active
Availability
Common
Build
Case capacity
69 gr H₂O
Twist (typical)
1:24
Primer
Large Rifle
Case type
Rebated
Pressure & range
Max pressure
38,500 psi
Eff. range
250 yd
Max range
1800 yd
Recoil
15–20 ft·lb

Ballistics

Published velocity/energy data isn't available for .450 Bushmaster. Parent case: .284 Winchester.

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.

Lazzeroni/MAST drawing · verified
Measuremmin✓
Bullet ⌀ 11.490.452 ✓
Neck ⌀ 12.190.480 ✓
Shoulder ⌀ n/a
Shoulder angle n/a
Base ⌀ 12.700.500 ✓
Rim ⌀ 12.010.473 ✓
Belt ⌀ n/a
Rim thickness 1.370.054 ✓
Neck length n/a
Case length 43.181.700 ✓
Overall length 57.402.260 ✓

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

Verification

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 →

Lil'Gun
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

12 models in the database chamber .450 Bushmaster. Browse all →

Springfield Armory SAINT Victor .450 Bushmaster 16-inchThompson/Center Arms Compass II 450 Bushmaster 16.5-inchChristensen Arms CA-10 G2 .450 Bushmaster 16-inchRuger AR-556 MPR .450 Bushmaster 16.1-inch (Folding)Ruger American Go WildSavage Arms MSR 15 .450 Bushmaster 16-inchRuger Gunsite Scout .350 Legend 16.5-inchRuger AR-556 MPR .450 Bushmaster 18-inchRuger American Rifle .450 Bushmaster 20-inchSavage 110 Magpul Hunter 308 WinAero Precision M4E1 450 Bushmaster 16-inchRuger Scout .450 Bushmaster 16.1-inch

Lineage

Immediate parent
.284 Winchester
Direct descendants (1)
.30 Remington AR
Family TreeOpen .450 Bushmaster in the interactive cartridge family tree

Connected reference

Loads66 factory loads for .450 BushmasterReloading1 suitable powder — cross-referenceFirearmsFirearms in .450 Bushmaster

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 →