Colt SCAR-B Clone Project

In 2003, the Special Operations Command (SOCOM) published a request for the ‘Special operations forces Combat Assault Rifle’ (SCAR). There were two types of rifles being requested. One rifle would be in 5.56x45mm NATO and would be the SCAR-L (Light). The other rifle would be chambered in 7.62×51 NATO and would be the SCAR-H (Heavy). Colt submitted three prototypes. These three prototypes were referred to as SCAR Type A, SCAR Type B and SCAR Type C.

Colt SCAR Type A and Type B were both direct impingement weapon systems

Colt SCAR Type A Prototype Photo: Chris Bartocci /Small Arms Solutions
Colt SCAR Type B Prototype Photo: Chris Bartocci / Small Arms Solutions

The two main differences between the Type A & Type B prototypes are that the Type A had the Colt modular upper receiver where as the Type B prototype used a standard M4 upper receiver in conjunction with the A.R.M.S. S.I.R. #58 MOD. Bi-Level Mid-Length rail system.

Colt SCAR Type C Prototype (Piston) Photo: Chris Bartocci / Small Arms Solutions

The Colt SCAR Type C was built on Colt’s piston design.

For additional information on the firearms above, see Chris Bartocci’s (Small Arms Solutions) excellent article at this link

In addition to being interested in Colt AR rifle and carbine designs, I have always had an affinity for the A.R.M.S. family of rail systems. Once I read Chris’s article about the SCAR Type A and B on the Small Arms Review website, I was hooked on the SCAR-B and decided that I would like to assemble a ‘clone’ of the carbine. For roughly four years I had been searching for the right A.R.M.S. rail. Since the entire clone concept for this carbine revolved around the correct rail, there was not point in looking for anything else. On December 20th of 2020 I got the opportunity to buy one of the A.R.M.S. rail systems from a firearms shop owner. Here is the rail system.

Left-side view of the A.R.M.S. S.I.R. #58 MOD. Bi-Level Mid-Length rail.
In this top view, you can see the rail designation: A.R.M.S. S.I.R. #58 MOD. Bi-Level Mid-Length

With the acquisition of this ‘unicorn’ piece, I began researching parts for the rest of the project. To come up with a parts list, I used Chris Bartocci’s article that was mentioned above and I also spoke to him some through private message. From reading the article and conversation, I came up with the following list:

  • Standard M-4 carbine upper receiver
  • A.R.M.S. S.I.R. #58 MOD. Bi-Level Mid-Length rail
  • A.R.M.S. #50 top rail (wingless)
  • A.R.M.S. sling swivel
  • A.R.M.S. #23 Quick Detach Throw Lever Pistol Grip
  • A.R.M.S. #40L rear sight (wingless)
  • VLTOR EMOD stock
  • Colt LE6940 gas block/folding sight assembly
  • Colt LE6920 lower receiver (no QR code)
  • Colt M4 upper receiver (using one from Cerro Forge)
  • Colt ambidextrous selector
  • Ambidextrous magazine release (Norgon)
  • Colt bolt carrier group
  • Knights Armament M4-QD compensator
  • Colt 1/7 HBAR barrel
  • Colt 9mm stainless steel trigger pins
  • Colt match trigger
  • Colt pistol grip

There are three features that I identified that I would not be able to replicate. They are:

  • 4-position selector (safe, semi, burst, auto)
  • Early design folding front sight (which is why I am using a Colt LE6940 gas block/folding front sight)
  • Special UTC weapon coating

From January of 2021 to today (8 August 2021) I gathered the parts shown above for this project. Over the coming week or two, I am going to post photos and discuss each part going into this project because several people have said that they are interested in learning more. During the time that I am putting this article together, the parts for the upper receiver will be off being assembled. So, stay tuned for more to come over the next several days.