20" Aero Precision & Faxon M5E1 Enhanced .308 WIN AR Upper Receiver (20F308Q-15E1KP)

$ 849.12

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Aero Precision

This complete custom 20" .308 WIN upper receiver has been designed and purpose built from start to finish for accuracy. Each is hand built by order from the highest quality components available with 16 demanding quality inspections along the way that must be passed before shipment. Absolutely zero inspection failures are allowed. 

Starting with a 7075 T-6 billet aluminum M5E1 (.308) stripped upper receiver from Aero Precision and Faxon's "Big Gunner" 20" .308 WIN Premium Series barrel this well thought-out upper receiver features a matched Aero Precision super light-weight 15" Keymod free-float handguard and is fully lapped for accuracy. 

IMPORTANT: Because these upper receivers are hand-built by order and because of the rigorous and demanding inspections and testing they must pass prior to shipment please allow up to 15 - 30 business days from your the date of your order for shipment.


  • Aero Precision M5E1 Assembled Upper Receiver - Hard Coat Anodized Black
  • Aero Precision 15" Gen 2 Enhanced Keymod Handguard - Hard Coat Anodized Black
  • Faxon Firearms "Big Gunner" 20" Premium Series .308 WIN Chambered Barrel - 4150 Gun Quality Steel, Heat Treated to RC 28-32 Hardness, and Stress Relieved, Salt Bath QPQ Black Nitride Finish
  • Ground Zero Precision Low Profile Steel Gas Block and Rifle-Length Seamless Stainless Steel Gas Tube
  • Product comes assembled

Aero Precision M5E1 Upper Receiver Features & Specifications:

  • Forged from 7075 T6 aluminum
  • Precision machined to our specs
  • M4 feedramps
  • Hard Coat Anodized - Black
  • .2795” takedown pin holes
  • Accepts all standard DPMS .308 components
  • Comes with forward assist and port door installed
  • Handguard mounting platform is forged into the receiver

Aero Precision Gen 2 Enhanced Keymod Handguard Features & Specifications:

  • Added quick disconnect sling socket at the 3, 6 and 9 o’clock positions
  • Milled additional surfaces along flats to aid with gripping and add visual appeal
  • New profile of the Picatinny Top Rail
  • 1pc free float design
  • Rail is Machined from 6061-T6 Aluminum
  • Hard Coat Anodized - Black
  • Built in Anti-Rotation tabs
  • Scalloped rails
  • Continuous top rail
  • 1.72" inside diameter fits most muzzle devices and 1.5" suppressors
  • Compatible with low profile gas blocks
  • Compatible with all properly spec'd Keymod rail sections & accessories.

Faxon Firearms "Big Gunner 20" Premium Series .308 WIN Barrel Features:

  • Twist: 1 in 10
  • Threading: 5/8 x 24
  • Material: 4150 Gun Quality Steel, Heat Treated to RC 28-32 Hardness, and Stress Relieved
  • Finish: Salt Bath QPQ Black Nitride
  • Gas Block Journal: .750
  • Gas System Length: Rifle Length
  • Weight: 2lb 9.8 oz
  • DPMS Barrel Extension
  • HP and MPI Tested

Aero Precision .308 / 7.62 Phosphated Bolt Carrier Group

Aero Precision's Phosphated .308 / 7.62 Bolt Carrier Group is the perfect firing mechanism for your big-bore rifle build. This high quality BCG features a mil-spec phosphate finish, is MPI/HPT and now includes a laser engraved Aero Precision "A" logo!

Bolt Carrier Group Features:

  • Material: Billet carrier machined from 8620 steel and case hardened
  • Finish: Mil-spec Phosphate coating
  • Gas Key: 4130 Steel attached with Grade 8 hardware and properly staked
  • Firing Pin: Machined from 8740 steel and hard chrome coated
  • Forward Assist serrations
  • Laser engraved Aero Precision logo
  • Carrier fits DPMS compatible style AR Rifles

Bolt Carrier Group Specifications:

  • Material: Case Hardened 9310 Steel
  • Finish: All bolt components are shot peened and phosphate coated
  • Extractor: Machined from 4340 Steel with double o-rings and double springs
  • Magnetic Particle Inspected and High Pressure Tested
  • High pressure bolt - external surfaces are CNC ground after heat treat for a precision fit and firing pin hole diameter is reduced to .070"
  • Multi-caliber bolt designed to function with .308, 7.62x51, 6.5 Creedmoor, .338 Federal and other .308 based cartridges.

Bolt Carrier Group Includes:

  • Bolt carrier
  • Complete bolt
  • Firing pin
  • Cam pin
  • Retaining pin