Aero Precision M4E1 6.5 Grendel Complete Upper Receiver - 20" Stainless Threaded Barrel - 15" ATLAS R-One Handguard - Black

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Aero Precision APAR700725M53: Upgrade the performance of your AR15 build with this 6.5 Grendel Complete Upper Receiver. Designed to be a low recoil/high accuracy cartridge, the 6.5 Grendel is ideal for those looking to stretch the legs of their AR15 rifle, with proven results at 1000+ yards.

This complete upper includes Aero Precision's new ATLAS R-ONE Handguard! The R-ONE handguards are designed with size and weight in mind, while still providing plenty of real-estate to accommodate any attachment needs the end user may have. Aero Precision's proprietary ATLAS attachment system is a durable and dependable mounting platform, maintaining a slim profile while still providing the strength and stability customers have grown to love from Aero Precision handguards. This upper assembly DOES NOT include a BCG or Charging Handle.


  • M4E1 Threaded Assembled Upper Receiver
  • 15" ATLAS R-ONE Handguard
  • 6.5 Grendel 20" Stainless Steel, Rifle Length Barrel
  • .750 Low Profile Gas Block and Rifle Length Gas Tube
  • A2-style Flash Hider
  • Product comes assembled
  • The 6.5 Grendel is designed on the AR15 platform. You will need to purchase a 6.5 Grendel specific bolt and magazine. All other components are standard to the AR15 platform.

M4E1 Threaded Upper Receiver Features:

  • New enhanced forging that gives the upper receiver a "billet look"
  • New picatinny profile that blends seamlessly with our Enhanced Series Handguards
  • M4 Feedramps
  • .250 takedown pin holes
  • Laser engraved T-marks
  • Includes port door and forward assist installed

ATLAS R-ONE Handguard Features:

  • Full top picatinny rail for optional attachments
  • Quick disconnect sling socket at the 3, 6 and 9 o'clock positions
  • Compatible with low profile gas blocks
  • 1.3" Inside diameter
  • 1.5" Outside diameter
  • Compatible with mil-spec AR15 upper receivers and barrels
  • 6.5 Grendel 20" Stainless Steel, Rifle Length Barrel Features:
  • 6.5 Grendel 20" Rifle Length Barrel
  • 416R Stainless Steel finish
  • 1/8 twist
  • 5/8x24 Threaded Pitch
  • DMR Profile
  • .750 gas block journal
  • Rifle length gas system
  • M4 Feed Ramp Extension
  • HP and MPI tested


  • SKU ACC-AERO-APAR700725M53
  • Country of Manufacture United States
  • License Requirement None
  • Manufacturer Aero Precision
  • Mfg. Part Number APAR700725M53
  • UPC 840014602261
  • Caliber/Gauge 6.5 Grendel
  • Barrel Length 20"
  • Condition New
caliber or gauge:
6.5 grendel
barrel length:
threaded barrel
made in usa
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