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Aero Precision 5.7 5" AR15 PDW Pistol Upper Group CQB Mk57 5.7x28mm AR-15 AR57
Aero Precision 5.7 5' AR15 PDW Pistol Upper Group CQB Mk57 5.7x28mm AR-15 AR57

Aero Precision 5.7 5" AR15 PDW Pistol Upper Group CQB Mk57 5.7x28mm AR-15 AR57

Part Number:AERO-57DBC33
On sale: $729.95
Retail Price:$869.95
You Save:$140.00(16%)
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Muzzle Device
Aero Precision 5.7 5" AR15 PDW Pistol Upper Group CQB Mk57 5.7x28mm AR-15 AR57

Add the LIGHTEST Aero Precision Complete 5.7 Pistol Upper Receiver with this 5" Barrel and reliable CMMG 5.7x28mm Radial Delayed Blowback System to any existing AR15 lower to add this powerful cartridge to your arsenal! The 5” barrel this is the smallest 5.7 CMMG® has to offer.

Radial Delayed Blowback™ Operating System
Originally developed for the .45 ACP MkG platform, CMMG has adapted the Radial Delayed Blowback system across their pistol caliber lineup to create pistols and rifles with a softer recoil impulse and reduced bolt weight compared tthan traditional straight blowback systems. Check out CMMG Resource articles & video to learn more about what sets Radial Delayed Blowback apart.

Ultralight and compact while bringing higher capacity and power, this 5.7 Upper Group is a fantastic Close Quarters CQB Personal Defensive Weapon PDW choice for your next Short Barreled Rifles (SBR’s- All NFA Rules Apply) or AR pistol build. 

Optional Muzzle Device Choices:

Strike Industries Warhog Mini Comp (pictured)
A2 Flash Hider
VG6 Gamma Brake
Strike Industries Cloak Hider
Levang Linear Compensator
Hera LCS Linear Compensator Small
Guntec Fake Suppressor


  • Aero AR15 Assembled Upper Receiver with No Forward Assist
  • Aero 4" M-LOK ATLAS R-ONE Handguard
  • XTS Ambidextrous Charging Handle INCLUDED
  • CMMG 5” 1:9 Twist, Medium Taper 4140 SBN
  • Product comes assembled with CMMG's Lifetime Quality Guarantee
  • The muzzle device that comes with this complete upper receiver must be selected and is NOT pinned nor welded to this barrel. NO MAGAZINE INCLUDED UNLESS ADDED.

Aero AR15 Upper Receiver with No Forward Assist Features:

  • M4 Feedramps
  • Forged 7075-T6 Aluminum
  • .250 takedown pin holes
  • Laser engraved T-marks
  • Port door 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
  • Learn More about our NEW ATLAS Hanguards

5" 5.7mm Pistol Length Barrel Features:

  • Chamber: 5.7mm
  • Length: 5"
  • Twist: 1 in 9
  • Threading: 1/2"x28
  • Material: Chrome Moly Vanadium
  • Finish: QPQ corrosion resistant finish both inside and out
  • Gas System: Delayed Blowback
  • M4 Barrel Extension

Shipping to FFL Dealer RequiredNo
Made In America?Yes
Barrel Length5"
FinishAnodized Black
Weight2lbs 6oz Including BCG and Charging Handle

Optional ADD-ON:

32 Round Mag
CMMG’s GEN2 5.7 AR Conversion Magazine holds 32 rounds of 5.7x28mm and fits in any standard AR15 lower receiver. To use, simply attach a CMMG 5.7x28mm Radial Delayed Blowback complete upper receiver to an existing AR15 lower. Then, insert CMMG’s 5.7 AR Conversion Magazine to safely feed 5.7x28mm ammunition. CMMG recommends using a standard carbine buffer and action spring to reliably cycle the action in this configuration. The 5.7 AR Conversion Magazine also retains last round bolt hold-open functionality, allowing for faster reloads.

CALIBER: 5.7x28mm
CAPACITY: 32 rounds
WEIGHT: 8oz(unloaded)

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