M4A1 SOCOM Block 2 FSP Upper Receiver, Military Special

Generally available item, made to order
Custom Built to Order:
Allow 3 to 5 weeks to pin flash hider and build and ship

M4A1 Block 2 FSP Upper Receiver, 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 Cage Code (or optional "C" marked) 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.

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.

 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 for $100.  Contact us at check-out if you want this option.  Yes, we realize that $100 for pin and weld is high, but 1) we use the best craftsman in the business, 2) the upper receiver, barrel, rail, gas tube and FSB must be assembled prior to the muzzle device being pinned, and 3) the assembled upper is shipped out and then shipped back to us, so there is a cost. 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.
  • 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)

Pictures courtesy Potomac Armory, and the US Department of Defense

See also:  Colt M4A1 upper receiver with upgraded RAS