My Account (Sign in)
Your basket is empty.
0
Basket
contact us by phone Help and contact
Free standard delivery over £199
100-day return policy
My Account (Sign in)
Wish list
Your basket is empty. (0)
Basket
Newsletter Newsletter
Sale

Over 300,000 customers - we say thank you!

4.93/5 "Very good" (1400+ reviews)

40,000+ products for hunting and shooting sports

Rifle Parts Receiver Parts Receivers Upper Receivers AERO PRECISION M4E1 5.56 ASSM UPPR 18" RIFLE 12" ATLAS S-ONE HG BLK Support

The M4E1 5.56 Upper Receiver features a lightweight ATLAS S-ONE Handguard, durable construction, and options for 16" or 18" barrels, perfect for your build.

AERO PRECISION M4E1 5.56 ASSM UPPR 18" RIFLE 12" ATLAS S-ONE HG BLK

840014601622 100054451

Filters:

Variations
Filters:
Variations:

Variations:

The M4E1 5.56 Upper Receiver features a lightweight ATLAS S-ONE Handguard, durable construction, and options for 16" or 18" barrels, perfect for your build.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 18" RIFLE 12" ATLAS S-ONE HG BLK
832.6 GBP 0 £832.60 *
Not available
Cartridge: 5.56 mm NATO Color: Black Finish: Anodized Length: 18'' Make: AR-15 Style: Complete Twist: 1-7 Product no.: 100054451
Not available
832.6 GBP 0 £832.60 *
The Aero Precision M4E1 5.56 Upper features a lightweight ATLAS S-ONE Handguard, durable build, and options for 16" or 18" barrels, perfect for your AR15.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 11.5" CARBINE 9" ATLAS S-ONE HG BLK
589.9 GBP 0 £589.90 *
Not available
Cartridge: 5.56 mm NATO Color: Black Contour: M4 Finish: Anodized Length: 11.5'' Make: AR-15 Style: Complete Product no.: 100036051
Not available
589.9 GBP 0 £589.90 *
The Aero Precision M4E1 5.56 Upper features a lightweight ATLAS S-ONE Handguard, durable construction, and options for 16" or 18" barrels, perfect for custom builds.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 11.5" CARBINE 9" ATLAS S-ONE HG FDE
609.9 GBP 0 £609.90 *
Not available
Cartridge: 5.56 mm NATO Color: Flat Dark Earth Contour: M4 Finish: Anodized Length: 11.5'' Make: AR-15 Style: Complete Product no.: 100036052
Not available
609.9 GBP 0 £609.90 *
The Aero Precision M4E1 5.56 Upper features a lightweight ATLAS S-ONE Handguard, durable construction, and a choice of 16" or 18" barrels for versatile performance.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 16" MID-LEN 12" M-LOK ATLAS S-ONE HG BLK
797.8 GBP 0 £797.80 *
Not available
Cartridge: 5.56 mm NATO Color: Black Finish: Anodized Length: 16'' Make: AR-15 Style: Complete Twist: 1-7 Product no.: 100054449
Not available
797.8 GBP 0 £797.80 *
The M4E1 5.56 Assembled Upper features an ATLAS S-ONE Handguard, lightweight design, M4 feed ramps, and options for 16" or 18" barrels, perfect for your build.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 16" MID-LEN 15" M-LOK ATLAS S-ONE HG BLK
813.5 GBP 0 £813.50 *
Not available
Cartridge: 5.56 mm NATO Color: Black Finish: Anodized Length: 16'' Make: AR-15 Style: Complete Twist: 1-7 Product no.: 100054450
Not available
813.5 GBP 0 £813.50 *
589.9 832.6 5 GBP
832.6 GBP £832.60

Prices inclusive of duty & VAT.

Product no.: 100054451

Mfr. No.: APAR700305M8

840014601622 This complete upper includes Aero Precision’s new ATLAS S-ONE Handguard! The S-ONE line of handguards are designed with size and weight in mind, providing the perfect addition to your lightweight build. 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. M4E1 Threaded Assembled Upper Receiver Choice of 12” or 15” M-LOK ATLAS S-ONE Handguard 16" 5.56 Mid CMV Barrel, 18” Rifle Barrel Low Profile Gas Block and Mid-Length/Rifle Length Gas Tube Depending on Configuration Product comes assembled This complete upper does not include BCG or Charging Handle 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 S-ONE Handguard Features: Front and rear picatinny rail Eliminated center of top rail for weight reduction Indexing grooves in 12:00 position for positive grip control 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 16" 5.56 Mid Barrel Features: 5.56 NATO 16" Barrel, 1/7 twist, 4150 CrMoV, QPQ, gas port drilled Mid-length gas system, .0785 gas port M4 Feed Ramp Extension HP and MPI tested Standard A2 flash hider 18" 5.56 Rifle Length Barrel Features: 5.56 Nato 18" Rifle Length Barrel 4150 CrMoV w/ QPQ finish 1/7 twist .750 gas block journal Rifle length gas system M4 Feed Ramp Extension HP and MPI tested Standard A2 flash hider
Not available
Be the first to rate this product

Not available.

100-Day Return Policy
No charges until we ship
No charge:
Your credit card will not be charged when you place your order.

No commitments:
You are under no obligation until the goods are shipped. You can cancel your order at any time before shipping - free of charge.

Not until shipping:
Your credit card will only be charged once we ship your order. Not before.
Wish List Ask question
order by phone
589.9 832.6 5 GBP
Description Specification Customers reviews Accessories

AERO PRECISION M4E1 5.56 ASSM UPPR 18" RIFLE 12" ATLAS S-ONE HG BLK

832.6 GBP £832.60

Prices inclusive of duty & VAT.

Is a 'Call to order' product.
Requires order by phone

Description:

Upgrade your build with the M4E1 5.56 ASSEMBLED UPPER RECEIVER!

This complete upper includes Aero Precision’s new ATLAS S-ONE Handguard! The S-ONE line of handguards are designed with size and weight in mind, providing the perfect addition to your lightweight build.

Product Features:

  • M4E1 Threaded Assembled Upper Receiver
  • Choice of 12” or 15” M-LOK ATLAS S-ONE Handguard
  • 16" 5.56 Mid CMV Barrel, 18” Rifle Barrel
  • Low Profile Gas Block and Mid-Length/Rifle Length Gas Tube Depending on Configuration
  • Product comes assembled
  • This complete upper does not include BCG or Charging Handle
  • 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 S-ONE Handguard Features:

  • Front and rear picatinny rail
  • Eliminated center of top rail for weight reduction
  • Indexing grooves in 12:00 position for positive grip control
  • 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

16" 5.56 Mid Barrel Features:

  • 5.56 NATO 16" Barrel, 1/7 twist, 4150 CrMoV, QPQ, gas port drilled
  • Mid-length gas system, .0785 gas port
  • M4 Feed Ramp Extension
  • HP and MPI tested
  • Standard A2 flash hider

18" 5.56 Rifle Length Barrel Features:

  • 5.56 NATO 18" Rifle Length Barrel
  • 4150 CrMoV w/ QPQ finish
  • 1/7 twist
  • .750 gas block journal
  • Rifle length gas system
  • M4 Feed Ramp Extension
  • HP and MPI tested
  • Standard A2 flash hider

Experience the quality and precision of Aero Precision with the M4E1 5.56 ASSEMBLED UPPER RECEIVER, perfect for your next firearms project!



Restrictions

  • Is a 'Call to order' product.

Top takeaways

  1. The Aero Precision M4E1 Complete Upper Receiver features a lightweight ATLAS S-ONE Handguard and is designed for a 5.56mm NATO cartridge with an 18" barrel and 1-7 twist rate.
  2. It includes an enhanced forging for a billet look, M4 feed ramps, and is compatible with mil-spec AR15 upper receivers and barrels.
  3. The upper receiver does not come with a BCG or Charging Handle and has a black anodized finish, with the handguard offering multiple QD sling attachment points.

Attributes

  • Cartridge: 
    5.56 mm NATO
  • Colour: 
    Black
  • Contour: -
  • Finish: 
    Anodized
  • Length: 
    18''
  • Style: 
    Complete
  • Twist: 
    1-7
  • Weapon type: 
    AR-15
  • Delivery weight: 2.268kg
  • Shipping height: 102mm
  • Shipping width: 102mm
  • Shipping length: 775mm
  • UPC: 840014601622

Item details

Made in USA
US export classification: I(g)

Customers reviews

Customer ratings (0)

0 / 5

Variations:

The M4E1 5.56 Upper Receiver features a lightweight ATLAS S-ONE Handguard, durable construction, and options for 16" or 18" barrels, perfect for your build.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 18" RIFLE 12" ATLAS S-ONE HG BLK
832.6 GBP 0 £832.60 *
Not available
Cartridge: 5.56 mm NATO Color: Black Finish: Anodized Length: 18'' Make: AR-15 Style: Complete Twist: 1-7 Product no.: 100054451
Not available
832.6 GBP 0 £832.60 *
The Aero Precision M4E1 5.56 Upper features a lightweight ATLAS S-ONE Handguard, durable build, and options for 16" or 18" barrels, perfect for your AR15.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 11.5" CARBINE 9" ATLAS S-ONE HG BLK
589.9 GBP 0 £589.90 *
Not available
Cartridge: 5.56 mm NATO Color: Black Contour: M4 Finish: Anodized Length: 11.5'' Make: AR-15 Style: Complete Product no.: 100036051
Not available
589.9 GBP 0 £589.90 *
The Aero Precision M4E1 5.56 Upper features a lightweight ATLAS S-ONE Handguard, durable construction, and options for 16" or 18" barrels, perfect for custom builds.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 11.5" CARBINE 9" ATLAS S-ONE HG FDE
609.9 GBP 0 £609.90 *
Not available
Cartridge: 5.56 mm NATO Color: Flat Dark Earth Contour: M4 Finish: Anodized Length: 11.5'' Make: AR-15 Style: Complete Product no.: 100036052
Not available
609.9 GBP 0 £609.90 *
The Aero Precision M4E1 5.56 Upper features a lightweight ATLAS S-ONE Handguard, durable construction, and a choice of 16" or 18" barrels for versatile performance.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 16" MID-LEN 12" M-LOK ATLAS S-ONE HG BLK
797.8 GBP 0 £797.80 *
Not available
Cartridge: 5.56 mm NATO Color: Black Finish: Anodized Length: 16'' Make: AR-15 Style: Complete Twist: 1-7 Product no.: 100054449
Not available
797.8 GBP 0 £797.80 *
The M4E1 5.56 Assembled Upper features an ATLAS S-ONE Handguard, lightweight design, M4 feed ramps, and options for 16" or 18" barrels, perfect for your build.
M4E1 5.56 ASSEMBLED UPPER RECEIVER W/M-LOK ATLAS S-ONE HANDGUARD - M4E1 5.56 ASSM UPPR 16" MID-LEN 15" M-LOK ATLAS S-ONE HG BLK
813.5 GBP 0 £813.50 *
Not available
Cartridge: 5.56 mm NATO Color: Black Finish: Anodized Length: 16'' Make: AR-15 Style: Complete Twist: 1-7 Product no.: 100054450
Not available
813.5 GBP 0 £813.50 *

Oops! Something went wrong.

We encountered an error while loading this content. Please refresh the page to continue. If the issue persists, contact our customer support.

Site Navigation
Product Categories
Ordering
Customer Service

Welcome!

to Brownells UK, your destination for anything gun related. With our roots in a genuine passion for firearms, we bring you an unmatched selection of Gun Parts, Firearm Accessories, Gunsmithing Tools, Scopes & Red Dot Sights and Expert Knowledge.

Whether you're looking to maintain, repair, or upgrade, we've got what you need!

For Shooters, By Shooters
We share your enthusiasm and know exactly what you're looking for because we're part of the community.

Massive Selection
From the essentials to the unique, find everything under one roof.

Our blend of tradition and innovation
Shop with the convenience of modern technology, backed by a legacy of experience.

Browse our collection and discover why we're the trusted name in shooting sports & hunting.

Brownells Norge - Komplett utvalg av ladeutstyr, våpendeler, kuler, hylser, kikkerter, optikk og luftvåpen Brownells Österreich - Einer der größten Lieferanten für Waffenteile, Büchsenmacherzubehör & Schießsportzubehör Brownells Switzerland - Einer der größten Lieferanten für Waffenteile, Büchsenmacherzubehör & Schießsportzubehör Brownells Deutschland - Einer der größten Lieferanten für Waffenteile, Büchsenmacherzubehör & Schießsportzubehör Brownells France - Le plus grand fournisseur d'Accessoires pour le tir, Pièces détachées & Outils d'Armurier Brownells Iberica - El mayor proveedor de accesorios para el Tiro, Piezas y herramientas del armero. Brownells Sverige - Världens största leverantör av Vapendelar, Vapensmide Verktyg & Skyttetillbehör Brownells Suomi Brownells Italia - Il negozio del più grande rivenditore di componenti e accessori per armi da tiro, difesa e caccia Brownells Polska - Największy na świecie dostawca części broni, narzędzi rusznikarskich & akcesoriów strzeleckich Brownells Česko - Největší světový dodavatel součástí zbraní, střeleckého příslušenství a zbrojního nářadí
*
Prices inclusive of duty & VAT.

© 2025 Brownells UK
Part of the Brownells Europe Group

Logo Brownells
Classical viewClassical view Mobile viewMobile view
Back to top