M4A1 Block 2 FSP SOPMOD - SOCOM Upper Receiver Assembly, Military Special

This is top shelf.  You might not need top shelf, but if you want it, this is it.  Charlie's Custom M4A1 with the FSP / front sight base and all the bells and whistles.  Period correct.  Dope! 

We held nothing back with this upper receiver group.  Colt upper receiver, Colt SOCOM 14.5" barrel with Surefire 4-prong flash hider, Daniel Defense M4A1 FSP rail in FDE, Colt BCG, and Tango Down Scar Panels and Vertical Forward Grip in FDE.  The Block 2 is a great rifle, and some like the flattop rail, but there is just something that says classic about the Front Sight Base rig.

The M4A1 SOPMOD Block 2 Upper Receiver Group with front sight post (FSP) is a significant component in the evolution of the M4 carbine platform used by the United States military. SOPMOD stands for Special Operations Peculiar Modification, a program initiated in the 1990s to enhance the M4 carbine's versatility and effectiveness for special operations forces.

The SOPMOD program aimed to create a modular weapon system that could be quickly adapted to various mission requirements. This involved developing a suite of accessories and modifications that could be easily attached or removed from the base M4 carbine, including optics, lasers, lights, and other tactical enhancements.

Highlights

• Colt Upper Receiver: We have square (Brass Aluminum) with Cage Code and, in limited quantities, keyhole (Cerro Forge).  You can make a request for one or the other, but no guarantees.  We do not stock them differently.  OPTIONAL "C" stamping from circa 2013 (call for pricing).

• Daniel Defense M4A1 FDE rail for FSP. If you would rather have the rail in Black, just add that preference in the order notes.

• Colt 14.5" SOCOM profile barrel, standard chrome-lined 1:7 5.56 NATO CAGE Code marked, with option for "C" marked barrel (call for pricing)

• Properly timed Surefire 4-prong SOCOM flash hider (FH556RC 1/2-28), with an option to have pinned and welded.  

• Colt factory Bolt Carrier Group. Most will have a 'C' stamped on the left side, some will have a white dot on the bolt, others will have both.

• Colt charging handle

• Tango Down FDE full vertical grip and two Tango Down FDE Scar rail panels (one for right side and one for left side)

Ready to pick your optic and/or rear back-up sight of your choice.  Charlie's likes the Matech 600 meter for iron sights, and your choice of a tan EOTech or Aimpoint M68 sight with a Wilcox mount, or maybe an Elcan with RMR.  You can even put a Trijicon ACOG on if you wish.  Just be sure to match this up with a Colt lower, laser-cut ID sticker and B5 SOPMOD Coyote stock and a sling for your rig.

Built to Charlie's specifications by Potomac Armory.

The Block 2 upper receiver group, including the FSP version, was first introduced in the mid-2000s as an upgrade to the original Block 1 configuration. The U.S. Naval Surface Warfare Center Crane Division played a crucial role in developing and testing these upgrades. The Block 2 upper was primarily used by U.S. Special Operations Command (SOCOM) units, including Navy SEALs, Army Special Forces, and other elite units.

Comparing the Block 1 and Block 2 versions:

Block 1:

• Featured a shorter handguard
• Used the Knight's Armament Company (KAC) Rail Interface System (RIS)
• Limited rail space for accessories

Block 2 (standard):

• Introduced the Daniel Defense RIS II handguard
• Longer handguard providing more rail space
• Improved heat dissipation
• Better ergonomics and modularity

Block 2 with FSP:

• Retained the front sight post of the original M4
• Slightly shorter handguard than the standard Block 2
• Maintained a more traditional appearance while offering enhanced functionality

The key difference between the two Block 2 versions is the presence or absence of the front sight post. The FSP version was developed to maintain compatibility with existing M4 barrels that had permanently attached front sight bases. This allowed for easier and more cost-effective upgrades of existing rifles. The non-FSP version, on the other hand, uses a low-profile gas block, providing a cleaner look and potentially better compatibility with certain optics and accessories.

Military rifle clone enthusiasts have shown great interest in the M4A1 SOPMOD Block 2 upper assembly, particularly the FSP version. This enthusiasm stems from several factors:

• Historical significance: The Block 2 FSP upper represents a specific era in U.S. military small arms development and has been used in numerous high-profile operations.
• Authenticity: Clone builders strive to recreate military-issue rifles as accurately as possible, and the Block 2 FSP upper is a crucial component in achieving this goal.
• Versatility: The modular nature of the SOPMOD system allows enthusiasts to customize their builds with various accessories and configurations.
• Aesthetic appeal: Many enthusiasts appreciate the blend of modern features with the classic appearance provided by the front sight post.

The M4A1 SOPMOD Block 2 with FSP represents a significant milestone in the evolution of the M4 platform. Its development through the SOPMOD program has resulted in a highly modular and effective weapon system that has seen extensive use by U.S. special operations forces. The enthusiasm of clone builders and the efforts of companies like Charlie's Custom Clones have brought this military technology to the civilian market, allowing firearm enthusiasts to experience and appreciate the engineering and design that goes into modern military small arms.

For pin and weld service, add here:  custom pin and weld muzzle device.  Add to your cart if you want this option.  Yes, we realize that our pin and weld service is a little on the high side, but, we use the best craftsman in the business.  Note that as-is (not pinned), a 14.5" could be creating an NFA firearm, and you must fully understand and comply with the law.  We also have other flash hider options, if a 4-prong is not what you need or want, less expensive options are available.  Ask us.

Pictures courtesy Potomac Armory, clonerifles.com and the US Department of Defense

See also:  Colt M4A1 upper receiver with upgraded RAS 

So what's up with Charlie's?

Charlie's Custom Clones (CCC) has played a significant role in bringing authentic clone rifles and upper receivers to the civilian market. As the largest clone rifle and component dealer in the United States, CCC has made it easier for enthusiasts to access hard-to-find parts and complete upper assemblies that closely match military specifications.

CCC's contributions to the clone building community include:

• Sourcing and offering authentic or near-authentic components: CCC has worked to provide civilians with parts that closely match those used by the military, including hard-to-find items like the Daniel Defense RIS II handguard.
• Complete upper assemblies: By offering fully assembled upper receivers, CCC has made it more convenient for enthusiasts to build their clone rifles without the need to source individual components.
• Innovation in clone rifles: CCC has expanded beyond the M4A1 platform, offering components and complete builds for other military rifles such as the Mk18, Mk12, and Mk13. This has allowed enthusiasts to explore a wider range of military small arms history.
• Education and resources: CCC has provided valuable information to the clone building community, helping enthusiasts understand the nuances of different military configurations and the components required to recreate them accurately.
• Customization options: While focusing on authenticity, CCC has also offered customization services to help enthusiasts create personalized versions of military-inspired rifles.