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  • Post last modified:August 19, 2023

If you are looking to build a 14.5" barrel M4A1 to clone your favorite military standard issue SOPMOD configuration or M4A1 CQBR.

Here are 4 best M4A1 upper clones you can buy with factory compete uppers and low cost upper where you can add custom parts to make yours more unique.

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M4A1 Upper Clone Buying Guide

The Daniel Defense M4A1 is the ultimate full length warfighter rifle designed to deliver unbeatable performance, reliability, and value in tight spaces.

While there are many different versions to meet specific operational requirements for United States military and law enforcement agencies.  The M4A1 uses a 14.5" barrel from tip to tip. While regular AR15 features a 16" barrel.
Some of the notable M4A1 variants include:

  • Block 1 and Block 2
  • M4A1 CQBR
  • M4A1 MWS

The M4A1 upper features a heavier barrel to shoot hotter NATO 5.56, but the rest are similar to regular. If you want to clone the rifle to have exact parts as a military standard issue, please check out the compete upper receiver to buy.

Customize AR15 with hand pick upgrade parts here

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Top M4A1 Upper Clones

Daniel Defense M4A1 Block 2 Upper - Best For SOPMOD Block II Build

daniel defense m4a1 sopmod block 2 upper

This Daniel Defense M4A1 upper has a 14.5-inch barrel with pinned and welded muzzle device to make it an overall 16-inch barrel that is civilian legal. This upper is the ultimate choice to build out a true military M4A1 SOPMOD block 2 configuration rifle based on the USGI standard.

Key Features:

  • CNC machined 6061 T6 aluminum RIS II rail with Bolt-Up System that won't twist easily. It's rigorously tested by USSOCOM, and it can also mount a M203 grenade launcher
  • Mil-Spec free float quad rail handguard to mount accessories like flashlights, night vision illuminators, and other add-ons without affecting the barrel's harmonics
  • All mil spec MP teste bolt carrier group with staked gas key
  • Low profile carbine length gas block made of 4140 harden steel with heavy phosphate coating
  • Santoprene made rail panels to withstand up to 300°F

Daniel Defense M4A1 FSP Upper - Best SOPMOD Block II Build With Iron Sights

daniel defense m4a1 fsp upper

This is the same upper receiver as the Daniel Defense M4A1 SOPMOD Block 2 recommended above. The only difference is the handguard is made for 14.5" profile barrel with A1.5 fixed rear sight and F marked front sight base.

The RIS II picatinny quad rail extends forward and has opening to clear the front sight base.

The muzzle is the Surefire SF3P Flash Hider precision machined from US mill-certified heat treated stainless steel bar stock, and it's pinned and welded to the barrel.

If you can't find a compete upper, you can also the a basic 16" upper from PSA and buy the Daniel Defense FSP RIS II handguard to finish the build.

PSA 10.5" 5.56 NATO Upper - Best For M4A1 CQBR Build

PSA 10.5 5.56 NATO Upper

The PSA 10.5" 5.56 NATO classic upper features the everything you need to further upgrade the upper into a M4A1 CQBR configuration for just under $200. The user can swap out the polymer handguard and replace it with any 7" handguard to make it into a M4A1 MWS, or M4A1 Block 3 with the Geissele URGI MK16 M LOK rail.   

This is one of the hottest selling upper from Palmetto State Armory for the price because its all build in house without middleman cost.

  • Trusted in house manufacturing: Palmetto State Armory is renowned for producing mil-spec and affordable AR-15s and AR parts using the same machines as Beretta, FN and Colt
  • F-Marked front sight post: This is correct for anyone interested in building a M4A1 CQBR
  • 10.5-inch barrel: This is the appropriate length for the Mod 0, and the barrel is made of high-quality Chrome Moly Vanadium steel, featuring a 1:7 twist rate and an extremely durable Phosphate coating.
  • Carbine-length gas system: This enhances the weapon's performance and reliability.
  • A2 flash hider and classic military-styled handguards: User can remove it for something else better

Aero Precision M4E1 14.5" Mid Length - Best For The Money

aero precision m4e1 14.5 upper

Aero Precision is another favorite manufacturer for AR-15s receivers with the Laser engraved T-marks known for their high-quality products at reasonable prices.

The M4E1 14.5″ Complete Upper Receiver with the Atlas S-One Handguard is an excellent choice for a M4A1 upper clone project on budget

Note the muzzle brake that comes with this upper may not be pinned nor welded to the barrel. Per the National Firearms Act, the muzzle brake MUST be pinned and welded to achieve the necessary 16" as defined by the ATF for a rifle build.

  • High-quality 14.5-inch barrel:  The barrel is made from Chrome Moly Vanadium steel and featuring a 1:7 twist rate with a mid length gas system.
  • HP and MPI bolt carry group: The Mil Spec BCG is expected to last as long 
  • Unique upper receiver design: The Aero Precision upper receiver has a distinctive 'billet look' even though it's forged, making it stronger and more lightweight.
  • Easily add QD sling - Quick disconnect sling socket at the 3, 6 and 9 o'clock positions
  • 9-inch ATLAS S-One handguard: This innovative handguard features unique aesthetics, and it also improves ergonomics and comfort by removing some of the Picatinny railing at the top. 
  • Versatile railing options: Mount accessories on the MLOK rails in the 3, 6, and 9 o'clock positions.

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