Great Lakes Firearms AR-15 .450 Bushmaster 18" Bronze/Stainless Steel 5-Round Rifle

The Great Lakes Firearms AR-15 .450 Bushmaster is a purpose-built semi-automatic rifle engineered for hunters and shooters who want serious stopping power in a modern platform. Chambered in .450 Bushmaster—a cartridge purpose-designed for AR-15 rifles—this 18-inch barreled rifle delivers the knockdown energy hunters expect while maintaining the ergonomics and modularity of the AR platform. At 6.4 lbs, it's light enough for a day in the field without sacrificing the durability you need when it counts.

Great Lakes Firearms equipped this rifle with a high-quality aluminum upper and lower (7075-T6 for both) that provide the structural rigidity necessary for reliable, consistent performance. The 18-inch barrel features either 416R stainless steel or 4150 CRMOV with nitride finish, both excellent choices for durability and corrosion resistance in varied hunting conditions. The 1:24 twist rate is optimized for .450 Bushmaster ballistics, and the barrel wears a factory-included muzzle brake designed to be torqued without threadlocker—a nice detail that shows attention to setup and maintenance.

The rifle ships with a full-length aluminum handguard (15.25 inches of 6061-T6) topped with continuous Picatinny rail real estate, giving you genuine flexibility for mounting lights, optics, or other modern accessories. A mil-spec trigger breaks at 5.5–6 lbs—predictable and reliable—and the gas system uses a mid-length tube with a 0.750 adjustable gas block, balancing reliability and recoil management. One 5-round magazine is included; the modified M4 feed ramps ensure dependable feeding of the larger .450 case. The rifle arrives with no sights, so you'll start fresh with the optic setup that suits your hunting style.

This is a rifle built for hunters who know what .450 Bushmaster can do and want it in a shooter-friendly package that doesn't compromise on fit and finish.

Key Features

• 18-inch barrel optimized for .450 Bushmaster with 1:24 twist
• Lightweight at 6.4 lbs for field carry without sacrificing durability
• 7075-T6 aluminum upper and lower receivers for structural integrity
• Mid-length gas system with adjustable 0.750 gas block for reliable cycling
• 15.25-inch handguard with full-length Picatinny rail for accessory mounting
• Factory muzzle brake included and pre-designed for wrench installation
• Mil-spec 5.5–6 lb trigger for consistent trigger control
• One 5-round magazine included; modified M4 feed ramps for reliable feeding
• Choice of 416R stainless or nitride-coated 4150 CRMOV barrel finish
• No iron sights—clean slate for your optic choice

Specifications

Frequently Asked Questions

What's included in the box?

You get the rifle itself, one 5-round magazine, and the muzzle brake is already designed and factory-assembled. No sights are included, so you'll need to add an optic or backup sights of your choice.

Can I swap out barrel materials—stainless or nitride coated?

Yes. Great Lakes Firearms offers this rifle with either a 416R stainless steel barrel or a 4150 CRMOV barrel with nitride finish. Both are durable; stainless offers corrosion resistance without a coating, while nitride provides a harder surface finish. Choose based on your environment and maintenance preference.

Is this suitable for hunting?

Absolutely. The .450 Bushmaster cartridge is purpose-designed for hunting applications where you need significant stopping power. The 18-inch barrel, manageable recoil thanks to the mid-length gas system, and light weight make this rifle practical for field use.

What optics and accessories can I mount?

The 15.25-inch handguard features continuous Picatinny rail along its top surface, so you can mount any standard Picatinny-compatible optic, light, or other accessory. There are no sights pre-installed, giving you a clean platform to build your setup.