AUTHORITY ELITE AR15/M4 7.5" 300BLK Complete Billet Upper Receiver

Turn your build into a high-performance short-barrel 300 AAC Blackout (300BLK) rifle with this complete billet upper receiver assembly — including a precision 7.5" barrel, full-auto rated BCG, and the RACK-15 ambidextrous charging handle. Built from aerospace-grade materials and finished for durability, this upper is ready for duty, range days, or compact SBR builds (local laws apply).

Key Features

• Complete billet AR15/M4 upper receiver assembly — ready to mount on your lower
• 7.5" chambered barrel in .300 AAC BLACKOUT (300BLK) — optimized for subsonic & supersonic use
• Precision CNC 7075-T6 billet upper receiver with MIL-SPEC feed ramps
• Full-auto rated bolt carrier group (BCG) — MPI & magnetic particle inspection where applicable
• RACK-15 ambidextrous charging handle for fast, ergonomic manipulation from either side
• Free-float M-LOK handguard (lightweight, modular mounting for accessories)
• Durable finish — hardcoat anodized exterior for corrosion and wear resistance
• Precision headspaced and test-fired (headspace & test results provided at time of build where required)

Specifications

• Caliber: .300 AAC BLACKOUT (300BLK)
• Barrel Length: 7.5 inches
• Barrel Material: 41xx/4150 CMV steel (nitride/QPQ finish) — confirm finish option
• Twist Rate: 1:7" (optimized for subsonic & supersonic)
• Upper Receiver: CNC Machined 7075-T6 Billet — forward assist & ejection port
• BCG: Full-auto rated, Carpenter 158 style bolt, MPI inspected (standard)
• Charging Handle: RACK-15 Ambidextrous Charging Handle
• Handguard: Free-float M-LOK handguard (length matched to barrel)
• Muzzle: Threaded (commonly 5/8x24 or 1/2x28 — confirm threading)
• Finish: Hardcoat anodized (black) — other finishes available by request
• Weight (approx): ~2.2–2.8 lbs (varies by configuration)
• Included: Upper receiver, barrel, BCG, RACK-15 charging handle, handguard, barrel nut & mounting hardware
• FFL Required: Yes — sells as a firearm component in jurisdictions where applicable
• SKU: AE-UPR300BK-7.5 (replace with your SKU)

What’s in the Box

• AUTHORITY ELITE® Billet Upper Receiver (assembled)
• 7.5" 300BLK Barrel (pre-installed)
• Full-auto rated BCG
• RACK-15 Ambidextrous Charging Handle
• Free-float M-LOK Handguard
• Barrel nut, gas tube (if applicable), and all required mounting hardware

Usage & Compatibility

Designed to mate with any mil-spec AR-15/M4 lower receiver. Compatible with standard AR-15 bolts and magazines rated for 300BLK. Ideal for compact patrol, truck guns, SBR builds (where legally authorized), and short-barrel hunting or CQB setups. Always ensure your lower and any SBR paperwork/registration are in compliance with local, state, and federal law.

Notes & Options

• Barrel threading and finish options may vary — verify threading (commonly 1/2x28 or 5/8x24) before ordering suppressors or muzzle devices.
• Want a different twist rate, barrel profile, or finish? Contact us for custom build options.
• We can ship as a completed upper or provide drop-in barrel/handguard options per your checkout selection.

Warranty, Safety & Legal

AUTHORITY ELITE® products carry a limited warranty against defects in materials and workmanship. Warranty terms vary by component — contact us for full warranty details. Purchaser is responsible for compliance with all federal, state, and local laws. An FFL may be required to receive or transfer this item depending on jurisdiction.

WARNING — California Proposition 65: This product can expose you to chemicals including lead and other substances known to the State of California to cause cancer and birth defects or other reproductive harm. For more information visit www.P65Warnings.ca.gov.

Shipping & Returns

We ship to FFLs only for firearms and firearm receivers where required. Standard processing time is 1–3 business days unless custom options are selected. Returns accepted per our returns policy — opened/installed parts may be subject to restocking fees. Contact us for shipping instructions if you need an SBR configuration or special paperwork.

Technical Resources & Support

Installation instructions, torque specs, and maintenance guidelines are available on request. We recommend installation by a qualified gunsmith for best results and proper headspacing.