Small Arms Review
  • Home
  • Articles
    • Guns & Parts
    • Suppressors
    • Optics & Thermals
    • Ammunition
    • Gear
    • News & Opinion
    • Columns
    • Museums & Factory Tours
    • ID Guides
    • Interviews
    • Event Coverage
    • Articles by Issue
      • Volume 1
        • V1N1 (Oct 1997)
        • V1N2 (Nov 1997)
        • V1N3 (Dec 1997)
        • V1N4 (Jan 1998)
        • V1N5 (Feb 1998)
        • V1N6 (Mar 1998)
        • V1N7 (Apr 1998)
        • V1N8 (May 1998)
        • V1N9 (Jun 1998)
        • V1N10 (Jul 1998)
        • V1N11 (Aug 1998)
        • V1N12 (Sep 1998)
      • Volume 2
        • V2N1 (Oct 1998)
        • V2N2 (Nov 1998)
        • V2N3 (Dec 1998)
        • V2N4 (Jan 1999)
        • V2N5 (Feb 1999)
        • V2N6 (Mar 1999)
        • V2N7 (Apr 1999)
        • V2N8 (May 1999)
        • V2N9 (Jun 1999)
        • V2N10 (Jul 1999)
        • V2N11 (Aug 1999)
        • V2N12 (Sep 1999)
      • Volume 3
        • V3N1 (Oct 1999)
        • V3N2 (Nov 1999)
        • V3N3 (Dec 1999)
        • V3N4 (Jan 2000)
        • V3N5 (Feb 2000)
        • V3N6 (Mar 2000)
        • V3N7 (Apr 2000)
        • V3N8 (May 2000)
        • V3N9 (Jun 2000)
        • V3N10 (Jul 2000)
        • V3N11 (Aug 2000)
        • V3N12 (Sep 2000)
      • Volume 4
        • V4N1 (Oct 2000)
        • V4N2 (Nov 2000)
        • V4N3 (Dec 2000)
        • V4N4 (Jan 2001)
        • V4N5 (Feb 2001)
        • V4N6 (Mar 2001)
        • V4N7 (Apr 2001)
        • V4N8 (May 2001)
        • V4N9 (Jun 2001)
        • V4N10 (Jul 2001)
        • V4N11 (Aug 2001)
        • V4N12 (Sep 2001)
      • Volume 5
        • V5N1 (Oct 2001)
        • V5N2 (Nov 2001)
        • V5N3 (Dec 2001)
        • V5N4 (Jan 2002)
        • V5N5 (Feb 2002)
        • V5N6 (Mar 2002)
        • V5N7 (Apr 2002)
        • V5N8 (May 2002)
        • V5N9 (Jun 2002)
        • V5N10 (Jul 2002)
        • V5N11 (Aug 2002)
        • V5N12 (Sep 2002)
      • Volume 6
        • V6N1 (Oct 2002)
        • V6N2 (Nov 2002)
        • V6N3 (Dec 2002)
        • V6N4 (Jan 2003)
        • V6N5 (Feb 2003)
        • V6N6 (Mar 2003)
        • V6N7 (Apr 2003)
        • V6N8 (May 2003)
        • V6N9 (Jun 2003)
        • V6N10 (Jul 2003)
        • V6N11 (Aug 2003)
        • V6N12 (Sep 2003)
      • Volume 7
        • V7N1 (Oct 2003)
        • V7N2 (Nov 2003)
        • V7N3 (Dec 2003)
        • V7N4 (Jan 2004)
        • V7N5 (Feb 2004)
        • V7N6 (Mar 2004)
        • V7N7 (Apr 2004)
        • V7N8 (May 2004)
        • V7N9 (Jun 2004)
        • V7N10 (Jul 2004)
        • V7N11 (Aug 2004)
        • V7N12 (Sep 2004)
      • Volume 8
        • V8N1 (Oct 2004)
        • V8N2 (Nov 2004)
        • V8N3 (Dec 2004)
        • V8N4 (Jan 2005)
        • V8N5 (Feb 2005)
        • V8N6 (Mar 2005)
        • V8N7 (Apr 2005)
        • V8N8 (May 2005)
        • V8N9 (Jun 2005)
        • V8N10 (Jul 2005)
        • V8N11 (Aug 2005)
        • V8N12 (Sep 2005)
      • Volume 9
        • V9N1 (Oct 2005)
        • V9N2 (Nov 2005)
        • V9N3 (Dec 2005)
        • V9N4 (Jan 2006)
        • V9N5 (Feb 2006)
        • V9N6 (Mar 2006)
        • V9N7 (Apr 2006)
        • V9N8 (May 2006)
        • V9N9 (Jun 2006)
        • V9N10 (Jul 2006)
        • V9N11 (Aug 2006)
        • V9N12 (Sep 2006)
      • Volume 10
        • V10N1 (Oct 2006)
        • V10N2 (Nov 2006)
        • V10N3 (Dec 2006)
        • V10N4 (Jan 2007)
        • V10N5 (Feb 2007)
        • V10N6 (Mar 2007)
        • V10N7 (Apr 2007)
        • V10N8 (May 2007)
        • V10N9 (Jun 2007)
        • V10N10 (Jul 2007)
        • V10N11 (Aug 2007)
        • V10N12 (Sep 2007)
      • Volume 11
        • V11N1 (Oct 2007)
        • V11N2 (Nov 2007)
        • V11N3 (Dec 2007)
        • V11N4 (Jan 2008)
        • V11N5 (Feb 2008)
        • V11N6 (Mar 2008)
        • V11N7 (Apr 2008)
        • V11N8 (May 2008)
        • V11N9 (Jun 2008)
        • V11N10 (Jul 2008)
        • V11N11 (Aug 2008)
        • V11N12 (Sep 2008)
      • Volume 12
        • V12N1 (Oct 2008)
        • V12N2 (Nov 2008)
        • V12N3 (Dec 2008)
        • V12N4 (Jan 2009)
        • V12N5 (Feb 2009)
        • V12N6 (Mar 2009)
        • V12N7 (Apr 2009)
        • V12N8 (May 2009)
        • V12N9 (Jun 2009)
        • V12N10 (Jul 2009)
        • V12N11 (Aug 2009)
        • V12N12 (Sep 2009)
      • Volume 13
        • V13N1 (Oct 2009)
        • V13N2 (Nov 2009)
        • V13N3 (Dec 2009)
        • V13N4 (Jan 2010)
        • V13N5 (Feb 2010)
        • V13N6 (Mar 2010)
        • V13N7 (Apr 2010)
        • V13N8 (May 2010)
        • V13N9 (Jun 2010)
        • V13N10 (Jul 2010)
        • V13N11 (Aug 2010)
        • V13N12 (Sep 2010)
      • Volume 14
        • V14N1 (Oct 2010)
        • V14N2 (Nov 2010)
        • V14N3 (Dec 2010)
          • Ammunition
        • V14N4 (Jan 2011)
        • V14N5 (Feb 2011)
        • V14N6 (Mar 2011)
        • V14N7 (Apr 2011)
        • V14N8 (May 2011)
        • V14N9 (Jun 2011)
        • V14N10 (Jul 2011)
        • V14N11 (Aug 2011)
        • V14N12 (Sep 2011)
      • Volume 15
        • V15N1 (Oct 2011)
        • V15N2 (Nov 2011)
        • V15N4 (Jan 2012)
        • V15N5 (Feb 2012)
      • Volume 16
        • V16N1 (1st Quarter 2012)
        • V16N2 (2nd Quarter 2012)
        • V16N3 (3rd Quarter 2012)
        • V16N4 (4th Quarter 2012)
      • Volume 17
        • V17N1 (1st Quarter 2013)
        • V17N2 (2nd Quarter 2013)
        • V17N3 (3rd Quarter 2013)
        • V17N4 (4th Quarter 2013)
      • Volume 18
        • V18N1 (Jan Feb 2014)
        • V18N2 (Mar Apr 2014)
        • V18N3 (May Jun 2014)
        • V18N4 (Jul Aug 2014)
        • V18N5 (Sep Oct 2014)
        • V18N6 (Nov Dec 2014)
      • Volume 19
        • V19N1 (Jan 2015)
        • V19N2 (Feb Mar 2015)
        • V19N3 (Apr 2015)
        • V19N4 (May 2015)
        • V19N5 (Jun 2015)
        • V19N6 (Jul 2015)
        • V19N7 (Aug Sep 2015)
        • V19N8 (Oct 2015)
        • V19N9 (Nov 2015)
        • V19N10 (Dec 2015)
      • Volume 20
        • V20N1 (Jan 2016)
        • V20N2 (Feb Mar 2016)
        • V20N3 (Apr 2016)
        • V20N4 (May 2016)
        • V20N5 (Jun 2016)
        • V20N6 (Jul 2016)
        • V20N7 (Aug Sep 2016)
        • V20N8 (Oct 2016)
        • V20N9 (Nov 2016)
        • V20N10 (Dec 2016)
      • Volume 21
        • V21N1 (Jan 2017)
        • V21N2 (Feb Mar 2017)
        • V21N3 (Apr 2017)
        • V21N4 (May 2017)
        • V21N5 (Jun 2017)
        • V21N6 (Jul 2017)
        • V21N7 (Aug Sep 2017)
        • V21N8 (Oct 2017)
        • V21N9 (Nov 2017)
        • V21N10 (Dec 2017)
      • Volume 22
        • V22N1 (Jan 2018)
        • V22N2 (Feb 2018)
        • V22N3 (March 2018)
        • V22N4 (Apr 2018)
        • V22N5 (May 2018)
        • V22N6 (Jun Jul 2018)
        • V22N7 (Aug Sep 2018)
        • V22N8 (Oct 2018)
        • V22N9 (Nov 2018)
        • V22N10 (Dec 2018)
      • Volume 23
        • V23N1 (Jan 2019)
        • V23N2 (Feb 2019)
        • V23N3 (Mar 2019)
        • V23N4 (Apr 2019)
        • V23N5 (May 2019)
        • V23N6 (Jun Jul 2019)
        • V23N7 (Aug Sep 2019)
        • V23N8 (Oct 2019)
        • V23N9 (Nov 2019)
        • V23N10 (Dec 2019)
      • Volume 24
        • V24N1 (Jan 2020)
        • V24N2 (Feb 2020)
        • V24N3 (Mar 2020)
        • V24N4 (Apr 2020)
        • V24N5 (May 2020)
        • V24N6 (Jun Jul 2020)
        • V24N7 (Aug Sep 2020)
        • V24N8 (Oct 2020)
        • V24N9 (Nov 2020)
        • V24N10 (Dec 2020)
  • The Archive
    • Search The Archive
  • Store
    • Books
    • Back Issues
    • Merchandise
  • Podcast
  • Newsletter
  • Events
  • FrankenGun Challenge
  • About
    • About Small Arms Review
    • About Chipotle Publishing
    • Contact Us
    • Other Publications
      • Small Arms Defense Journal
  • Home
  • Articles
    • Guns & Parts
    • Suppressors
    • Optics & Thermals
    • Ammunition
    • Gear
    • News & Opinion
    • Columns
    • Museums & Factory Tours
    • ID Guides
    • Interviews
    • Event Coverage
    • Articles by Issue
      • Volume 1
        • V1N1 (Oct 1997)
        • V1N2 (Nov 1997)
        • V1N3 (Dec 1997)
        • V1N4 (Jan 1998)
        • V1N5 (Feb 1998)
        • V1N6 (Mar 1998)
        • V1N7 (Apr 1998)
        • V1N8 (May 1998)
        • V1N9 (Jun 1998)
        • V1N10 (Jul 1998)
        • V1N11 (Aug 1998)
        • V1N12 (Sep 1998)
      • Volume 2
        • V2N1 (Oct 1998)
        • V2N2 (Nov 1998)
        • V2N3 (Dec 1998)
        • V2N4 (Jan 1999)
        • V2N5 (Feb 1999)
        • V2N6 (Mar 1999)
        • V2N7 (Apr 1999)
        • V2N8 (May 1999)
        • V2N9 (Jun 1999)
        • V2N10 (Jul 1999)
        • V2N11 (Aug 1999)
        • V2N12 (Sep 1999)
      • Volume 3
        • V3N1 (Oct 1999)
        • V3N2 (Nov 1999)
        • V3N3 (Dec 1999)
        • V3N4 (Jan 2000)
        • V3N5 (Feb 2000)
        • V3N6 (Mar 2000)
        • V3N7 (Apr 2000)
        • V3N8 (May 2000)
        • V3N9 (Jun 2000)
        • V3N10 (Jul 2000)
        • V3N11 (Aug 2000)
        • V3N12 (Sep 2000)
      • Volume 4
        • V4N1 (Oct 2000)
        • V4N2 (Nov 2000)
        • V4N3 (Dec 2000)
        • V4N4 (Jan 2001)
        • V4N5 (Feb 2001)
        • V4N6 (Mar 2001)
        • V4N7 (Apr 2001)
        • V4N8 (May 2001)
        • V4N9 (Jun 2001)
        • V4N10 (Jul 2001)
        • V4N11 (Aug 2001)
        • V4N12 (Sep 2001)
      • Volume 5
        • V5N1 (Oct 2001)
        • V5N2 (Nov 2001)
        • V5N3 (Dec 2001)
        • V5N4 (Jan 2002)
        • V5N5 (Feb 2002)
        • V5N6 (Mar 2002)
        • V5N7 (Apr 2002)
        • V5N8 (May 2002)
        • V5N9 (Jun 2002)
        • V5N10 (Jul 2002)
        • V5N11 (Aug 2002)
        • V5N12 (Sep 2002)
      • Volume 6
        • V6N1 (Oct 2002)
        • V6N2 (Nov 2002)
        • V6N3 (Dec 2002)
        • V6N4 (Jan 2003)
        • V6N5 (Feb 2003)
        • V6N6 (Mar 2003)
        • V6N7 (Apr 2003)
        • V6N8 (May 2003)
        • V6N9 (Jun 2003)
        • V6N10 (Jul 2003)
        • V6N11 (Aug 2003)
        • V6N12 (Sep 2003)
      • Volume 7
        • V7N1 (Oct 2003)
        • V7N2 (Nov 2003)
        • V7N3 (Dec 2003)
        • V7N4 (Jan 2004)
        • V7N5 (Feb 2004)
        • V7N6 (Mar 2004)
        • V7N7 (Apr 2004)
        • V7N8 (May 2004)
        • V7N9 (Jun 2004)
        • V7N10 (Jul 2004)
        • V7N11 (Aug 2004)
        • V7N12 (Sep 2004)
      • Volume 8
        • V8N1 (Oct 2004)
        • V8N2 (Nov 2004)
        • V8N3 (Dec 2004)
        • V8N4 (Jan 2005)
        • V8N5 (Feb 2005)
        • V8N6 (Mar 2005)
        • V8N7 (Apr 2005)
        • V8N8 (May 2005)
        • V8N9 (Jun 2005)
        • V8N10 (Jul 2005)
        • V8N11 (Aug 2005)
        • V8N12 (Sep 2005)
      • Volume 9
        • V9N1 (Oct 2005)
        • V9N2 (Nov 2005)
        • V9N3 (Dec 2005)
        • V9N4 (Jan 2006)
        • V9N5 (Feb 2006)
        • V9N6 (Mar 2006)
        • V9N7 (Apr 2006)
        • V9N8 (May 2006)
        • V9N9 (Jun 2006)
        • V9N10 (Jul 2006)
        • V9N11 (Aug 2006)
        • V9N12 (Sep 2006)
      • Volume 10
        • V10N1 (Oct 2006)
        • V10N2 (Nov 2006)
        • V10N3 (Dec 2006)
        • V10N4 (Jan 2007)
        • V10N5 (Feb 2007)
        • V10N6 (Mar 2007)
        • V10N7 (Apr 2007)
        • V10N8 (May 2007)
        • V10N9 (Jun 2007)
        • V10N10 (Jul 2007)
        • V10N11 (Aug 2007)
        • V10N12 (Sep 2007)
      • Volume 11
        • V11N1 (Oct 2007)
        • V11N2 (Nov 2007)
        • V11N3 (Dec 2007)
        • V11N4 (Jan 2008)
        • V11N5 (Feb 2008)
        • V11N6 (Mar 2008)
        • V11N7 (Apr 2008)
        • V11N8 (May 2008)
        • V11N9 (Jun 2008)
        • V11N10 (Jul 2008)
        • V11N11 (Aug 2008)
        • V11N12 (Sep 2008)
      • Volume 12
        • V12N1 (Oct 2008)
        • V12N2 (Nov 2008)
        • V12N3 (Dec 2008)
        • V12N4 (Jan 2009)
        • V12N5 (Feb 2009)
        • V12N6 (Mar 2009)
        • V12N7 (Apr 2009)
        • V12N8 (May 2009)
        • V12N9 (Jun 2009)
        • V12N10 (Jul 2009)
        • V12N11 (Aug 2009)
        • V12N12 (Sep 2009)
      • Volume 13
        • V13N1 (Oct 2009)
        • V13N2 (Nov 2009)
        • V13N3 (Dec 2009)
        • V13N4 (Jan 2010)
        • V13N5 (Feb 2010)
        • V13N6 (Mar 2010)
        • V13N7 (Apr 2010)
        • V13N8 (May 2010)
        • V13N9 (Jun 2010)
        • V13N10 (Jul 2010)
        • V13N11 (Aug 2010)
        • V13N12 (Sep 2010)
      • Volume 14
        • V14N1 (Oct 2010)
        • V14N2 (Nov 2010)
        • V14N3 (Dec 2010)
          • Ammunition
        • V14N4 (Jan 2011)
        • V14N5 (Feb 2011)
        • V14N6 (Mar 2011)
        • V14N7 (Apr 2011)
        • V14N8 (May 2011)
        • V14N9 (Jun 2011)
        • V14N10 (Jul 2011)
        • V14N11 (Aug 2011)
        • V14N12 (Sep 2011)
      • Volume 15
        • V15N1 (Oct 2011)
        • V15N2 (Nov 2011)
        • V15N4 (Jan 2012)
        • V15N5 (Feb 2012)
      • Volume 16
        • V16N1 (1st Quarter 2012)
        • V16N2 (2nd Quarter 2012)
        • V16N3 (3rd Quarter 2012)
        • V16N4 (4th Quarter 2012)
      • Volume 17
        • V17N1 (1st Quarter 2013)
        • V17N2 (2nd Quarter 2013)
        • V17N3 (3rd Quarter 2013)
        • V17N4 (4th Quarter 2013)
      • Volume 18
        • V18N1 (Jan Feb 2014)
        • V18N2 (Mar Apr 2014)
        • V18N3 (May Jun 2014)
        • V18N4 (Jul Aug 2014)
        • V18N5 (Sep Oct 2014)
        • V18N6 (Nov Dec 2014)
      • Volume 19
        • V19N1 (Jan 2015)
        • V19N2 (Feb Mar 2015)
        • V19N3 (Apr 2015)
        • V19N4 (May 2015)
        • V19N5 (Jun 2015)
        • V19N6 (Jul 2015)
        • V19N7 (Aug Sep 2015)
        • V19N8 (Oct 2015)
        • V19N9 (Nov 2015)
        • V19N10 (Dec 2015)
      • Volume 20
        • V20N1 (Jan 2016)
        • V20N2 (Feb Mar 2016)
        • V20N3 (Apr 2016)
        • V20N4 (May 2016)
        • V20N5 (Jun 2016)
        • V20N6 (Jul 2016)
        • V20N7 (Aug Sep 2016)
        • V20N8 (Oct 2016)
        • V20N9 (Nov 2016)
        • V20N10 (Dec 2016)
      • Volume 21
        • V21N1 (Jan 2017)
        • V21N2 (Feb Mar 2017)
        • V21N3 (Apr 2017)
        • V21N4 (May 2017)
        • V21N5 (Jun 2017)
        • V21N6 (Jul 2017)
        • V21N7 (Aug Sep 2017)
        • V21N8 (Oct 2017)
        • V21N9 (Nov 2017)
        • V21N10 (Dec 2017)
      • Volume 22
        • V22N1 (Jan 2018)
        • V22N2 (Feb 2018)
        • V22N3 (March 2018)
        • V22N4 (Apr 2018)
        • V22N5 (May 2018)
        • V22N6 (Jun Jul 2018)
        • V22N7 (Aug Sep 2018)
        • V22N8 (Oct 2018)
        • V22N9 (Nov 2018)
        • V22N10 (Dec 2018)
      • Volume 23
        • V23N1 (Jan 2019)
        • V23N2 (Feb 2019)
        • V23N3 (Mar 2019)
        • V23N4 (Apr 2019)
        • V23N5 (May 2019)
        • V23N6 (Jun Jul 2019)
        • V23N7 (Aug Sep 2019)
        • V23N8 (Oct 2019)
        • V23N9 (Nov 2019)
        • V23N10 (Dec 2019)
      • Volume 24
        • V24N1 (Jan 2020)
        • V24N2 (Feb 2020)
        • V24N3 (Mar 2020)
        • V24N4 (Apr 2020)
        • V24N5 (May 2020)
        • V24N6 (Jun Jul 2020)
        • V24N7 (Aug Sep 2020)
        • V24N8 (Oct 2020)
        • V24N9 (Nov 2020)
        • V24N10 (Dec 2020)
  • The Archive
    • Search The Archive
  • Store
    • Books
    • Back Issues
    • Merchandise
  • Podcast
  • Newsletter
  • Events
  • FrankenGun Challenge
  • About
    • About Small Arms Review
    • About Chipotle Publishing
    • Contact Us
    • Other Publications
      • Small Arms Defense Journal
No Result
View All Result
Small Arms Review
No Result
View All Result
Home Articles

THE COLT SCAR WEAPONS TYPE C

SAR Staff by SAR Staff
August 2, 2022
in Articles, Articles by Issue, Search by Issue, V10N1 (Oct 2006), Volume 10
THE COLT SCAR WEAPONS TYPE C
Share on FacebookShare on Twitter

A burst of automatic fire from the Colt SCAR Type C. Notice the two fired cartridge cases ejecting from the carbine. This carbine was tested during the SCAR trials and was very used and abused. The ammunition being fired is Black Hills manufactured Mk262 Mod 1 77-grain Open Tip Match bullet.

By Christopher R. Bartocci

Last month we looked at Type’s A and B of Colt’s SCAR (Special operations forces Combat Assault Rifle) program. Both used the traditional gas impingement system as found in the M16/M4 family of weapons and fared very well in the trials. However, there was an unwritten requirement that SOCOM wanted a conventional piston operated weapon. They felt it would be more clean and reliable under the extreme circumstances that they operated under.

Colt set out to develop their own piston driven mechanism. Piston systems were nothing new to Colt as they had experimented with it many years ago. In the late 1960s to early 1970s, experimentation was going on at Colt, Rock Island and Winchester to develop a standard piston mechanism to deal with the problems the early rifles had with the switch-over to ball powder. This also was as a response to the publicity of the reliability of the AK47. In the end, a report in 1968 stated that the 10 prototype weapons performed about equal to the current M16A1 rifles. Colt developed the model 703 as a piston driven operating system. Although totally unlike the current SCAR design, it indicates that Colt had investigated this in the past. The 703 was a full-length rifle with a piston rod that was attached to the bolt carrier, much like the AK-type piston. By the time Colt had concluded the development of the 703, all the changes made to the M16A1 and ammunition made a piston-operated mechanism unnecessary.

Cover of the operator’s manual provided to SOCOM with the Colt SCAR-L – Type C.

The Colt 703 rifle when fired, the bullet would propel down the barrel, and gas was bled from the barrel into the gas cylinder created between the end of the piston rod and the front sight base. The piston rod, being attached to the bolt carrier group, would move rearward extracting and ejecting the fired cartridge case. When the bolt carrier group reaches it’s furthest rearward motion the buffer/buffer spring would drive the bolt carrier group forward stripping a round from the magazine, chambering it, and the bolt would lock into battery ready for the next shot.

Colt SCAR Type C

SOCOM’s unwritten requirement for a piston operated rifle was based upon their belief that this system kept the gun cleaner due to hot gasses not being blown into the bolt carrier causing fouling. This is especially true when being fired with a suppressor.

The Type C SCAR was not the first time Colt looked into the design of a piston operated gas system in the M16 weapon system. Shown is the Colt model 703 designed in the late 1960s to early ’70s. (Photo courtesy of Collector Grade Publications)

Colt began work to design their own piston system. With the requirement for a free-floated barrel, Colt opted to use their newly designed one-piece upper receiver. Keeping the legacy M4 platform was important as it was very user friendly. Once the shooter grasps the pistol grip, all manipulations of the selector and magazine catch can be made without manipulation of the shooters hand. The left hand will insert the loaded magazine a hit the bolt catch to reload. Due to the magazine dropping free and the bolt holding open on the last shot, reloading can be accomplished is seconds. An added benefit to keeping this platform was taking advantage of the existing familiarity of the operators’ use with the M4A1 carbine.

The Colt 703 disassembled. This is the basic AK47 piston system where the piston rod is connected to the bolt carrier. The lower receiver remained the standard lower. All modifications were made to the upper receiver. After modifications were made to the direct gas system to cope with the use of ball propellant, this design was dropped due to little to no benefit in reliability. (Photo courtesy of Collector Grade Publications)

The SCAR Type C Upper Receiver

The upper receiver chosen was the Colt proprietary one-piece upper receiver. This allowed the barrel to be mounted to the receiver and permitted to free float; increasing accuracy as well as assist in cooling. The upper receiver utilizes a forward assist assembly, fired cartridge case deflector and an ejection port dust cover. There is a continuous Mil-Std 1913 rail that goes from the top of the charging handle area to the front sight base. This will allow the mounting of multiple optics including night vision, reflex sight as well as a laser. The side rails allow the operator to mount flashlights or other accessories. The bottom portion of the rail is removable allowing the mounting of a grenade launcher. When the standard cover with the rail is on, a vertical pistol grip may be installed. During testing, the newly designed Grip Pod Systems vertical pistol grip was used. This vertical pistol grip/bipod is made of 7075 T6 aircraft aluminum, the same as the Colt SCAR receivers. The bottom of the grip turns into a spring-loaded bipod with a push of a button. When the operator drops to the prone position and engages the bipod, the carbine has a stable base for aimed firing. When the bipod is engaged and the weapon shouldered, the magazine will not snag on the ground.

Side views of the Colt Type C. Although it looks like an M4 carbine, it is quite different. Notice the new UCT Defense UltraChem (Universal Chem Tech) Nickel Boron finish on the bolt carrier as well as the ambidextrous selector lever with the new 90 degree travel. Note the folded front sight assembly.

The carbine utilizes the same BUIS (Back Up Iron Sight) as the Colt Type A. The rear sight is a modified Colt carrying handle rear sight. Colt took a standard carrying handle and removed the handle just leaving a lightweight rear sight. There are no sharp edges to snag. It is adjustable for elevation out to 600 meters and has two sight apertures. A 0 to 200-meter close and a long-range aperture. However, any BUIS can be used whether it be an ARMS #40 L or a Knight Armament BUIS.

The front sight is a Colt designed foldable front sight assembly attached to the gas block. This same front sight assembly was used on all three of Colt’s entries and was activated and locked by a button on the left side. This utilized a square 4-notch front sight post and is adjustable for elevation only.

The Colt Piston Operating System

Detail of the side of the receivers. Notice the retention of the forward assist and fired cartridge case deflector. The addition of an ambidextrous sling adapter is in place of the sliding receiver end plate. Also, the Colt BUIS (Back Up Iron Sight) is seen showing the adjustments for both windage and elevation. You can see the Norgon ambidextrous magazine catch as well as the 90 degree selector lever. Also, all Colt entries utilized the improved hammer/trigger pins made of stainless steel for additional strength during extended firing. Notice the “O2” written on both the upper and lower receivers. This is the Crane designation for the Colt Type C SCAR candidate.

The piston system is very simple and very reliable. In firearms design there are two basic piston systems. The first is where the piston/operating rod is directly attached to the bolt carrier such as the AK47/AKM. The second is the short-stroke tappet where the operating rod strikes the face of the bolt carrier driving the carrier rearward while the piston rod reciprocates back to its rested position in front of the firearm such as the AR18, SKS and FN FAL.

The system chosen by Colt is the latter. By going with the two-piece operating rod the weight may be decreased. Colt has been working on their piston systems for a couple of years in their model shop. In 2003, a prototype was made showing an early attempt of their system. Over the next couple years their design would be modified and perfected to the final system they chose for their SCAR candidate

Colt BUIS (Back Up Iron Sight). This design came from the standard M4/M16A4 detachable carrying handle with all unnecessary material removed as well as the edges smoothed to give the lightest and most compact sight possible.

The final system begins with their proprietary one-piece upper receiver. The barrel is secured to the inside of the receiver and the barrel left free-floating. The system consists of the op rod and return spring. The front of the system consists of the gas cylinder and the mechanism is locked into the weapon by a large pin in the front sight/gas block. There is a gas relief vent in front of the gas cylinder that vents through the front of the front sight assembly. Colt has tested this operating mechanism with over 18,000 rounds without cleaning and without failure. This piston system does not require routine maintenance during cleaning.

Top: Showing the top rail of the Colt one-piece upper receiver. Notice the continuous Mil-Std 1913 rail that runs from the rear of the receiver to the front sight assembly. This enables the mounting of numerous optics including reflex sight with a night vision scope. Center: Top view of the standard carbine version of the SCAR Type C. Notice the numerous vent holes to aid in cooling on the sides of the dovetail. Bottom: Bottom of the Colt one-piece upper receiver with the bottom of the hand guard removed. Notice the fact the carbine has a heavy barrel to better handle the excessive firing schedules demanded by SOCOM. This barrel is also free floating which aids in accuracy and cooling and no pressure is put on the barrel from utilizing a vertical pistol grip.

As the bullet travels down the barrel upon firing, the bullet passes the gas port and gas is directed into the gas expansion chamber, driving the piston rearward. The rear of the piston impacts a modified carrier key on the bolt carrier group driving the carrier group rearward. While the carrier group continues rearward, the piston rod returns to its forward resting position. On the bolt carrier group’s rearward travel the bolt unlocks, extracting and ejecting the fired cartridge case from the carbine. Then the compressed heavy buffer and spring return the carrier group forward stripping an unfired cartridge from the magazine, feeding it into the chamber, and then the bolt locks into the barrel extension. The carbine is ready for the next shot to be fired. Another benefit of the piston-operated system is the ability to set the cyclic rate of the weapon. Colt chose to make the SCAR Type C fire at 800 rounds per minute comparable to that of the M4A1 with Mk 262 Mod 1 ammunition.

Face of the front sight assembly. Notice the gas relief vent which sits behind the cylinder. Also notice the 4 position square front sight post. To the left is the button which is pushed in to engage and disengage the front sight.

The Bolt Carrier

The bolt carrier group looks very similar to the standard M16/M4 family of firearms but with one major change: a new bolt carrier key. Also, there are no gas rings on the bolt due to the expansion chamber being in the front sight assembly instead of the back of the bolt carrier group. Another innovation that Colt has done is to change the finish of the bolt and carrier. It has a proprietary UCT Defense UltraChem (nickel boron) finish to eliminate the need for any lubricant whatsoever. This slippery finish needs merely a wipe with a rag to clean. This coating also improves corrosion resistance. The extractor utilizes the improved gold extractor spring with the stronger black extractor buffer.

Top: An example of a very early machine shop prototype of Colt’s gas system. The piston rod is removed by pulling in to the rear and lifting up. The piston cylinder sits in the front sight assembly. There is a piston return spring as well to return the piston forward after it impacts the bolt carrier to force it rearward. Center: Disassembled prototype piston assembly. Notice the rod guide (rear), the return spring, the piston rod, as well as the cylinder. This design was altered due to the fact Colt used a one-piece upper receiver. The piston system would have to be inserted from the front of the front sight assembly instead of the top of the barrel. This early system utilized a standard M4 upper receiver. Bottom: Piston rod shown on top of the Type C upper receiver. The cylinder and return spring are not shown.
The right side of the Type C bolt carrier assembly. The entire assembly has the new UCT (Universal Chem Technologies) Nickel Boron finish. This finish virtually eliminated the need to lubricate. Notice the modified carrier key which has been cut back and modified for the piston rod to impact. No gas rings are needed and the carrier retains the forward assist notches.

The Barrel

As per specifications, the barrels come in two different lengths. The standard carbine barrel length is 14.5 inches and the CQC (Close Quarter Combat) barrel is 10.5 inches. Both barrels are heavy barrels to insure they can take the required heavy firing schedule demanded by SOCOM. The barrel utilizes the standard 1 turn in 7 inch rifling twist that is required to stabilize the Mk 262 Mod 1 ammunition currently in use by SOCOM. Additionally, as per requirements, a Knight’s Armament Quick Detach flash suppressor is installed for use with the silencer. The front sight base has a bayonet lug for mounting a bayonet on both barrels even though one cannot be mounted on the 10.5 inch barrel.

The chamber has been modified to comply with the “Over the Beach” requirement specified for the SEALS.

The Lower Receiver

The lower receiver is identical to the ones used on Type A and B. It is a standard M4A1 lower receiver with the modified selector lever. As per requirement, this ambidextrous selector operates over 90 degrees of travel (as opposed to the Colt standard of 180 degrees). After testing was completed, this change was not well received. The reasoning in unclear as to whether they were just too used to the standard or if it did not manipulate as fast as the original.

The magazine release is the patented Norgon ambidextrous version. The stock is the VLTOR stock with dual battery compartments for the optics. This is a standard four-position Colt buffer extension with a H2 buffer. Due to the carbine utilizing a heavy barrel, the buffer with 2 tungsten weights and 1 steel weight was necessary to prevent light strikes from bolt carrier bounce. Improved hammer/trigger pins are used that are manufactured of stainless steel. This increases service life especially with heavy volume of fire required of the SCAR weapon. The finish is done in the required flat earth finish (coyote brown) done by Kal-Guard.

Conclusions

The opportunity arose to test fire Colt’s Type C SCAR in their engineering range in the basement of the factory. There was little difference in the feel between the direct gas and the piston driven carbines and their cyclic rate was about the same. The carbine fired was quite worn and neglected from the SCAR trials. However, the carbine functioned flawlessly; firing nearly 500 rounds in 15 minutes. The bolt carrier group was completely dry without lubricant.

There seems to be little doubt that the next generations of M16/M4 carbines will be piston driven mechanisms. Colt plans to introduce a piston driven law enforcement carbine in early 2006.

With the SCAR program moving forward with procurement from FN Mfg. Inc., only time will tell how the new weapons will stack up compared to the M4A1 carbines currently in use. The SCAR trials were without a doubt the most grueling small arms testing in the world since the original Armalite AR-15 was pitted against the government designed M14. Lessons learned in this weapons development program will influence further research and development of further upgrades or new weapons designs of the future.

This article first appeared in Small Arms Review V10N1 (October 2006)

Author

  • SAR Staff
    SAR Staff

    View all posts

Tags: 2006AK47AR18Back Up Iron SightBartocciBUISChristopher R. BartocciColtColt SCAR WeaponsFN-FALGrip Pod SystemsM16/M4M16A1M4M4A1Mk 262 Mod 1Rock IslandSCARSKSSOCOMUCT Defense UltraChemV10N1Winchester
Previous Post

U.S. SERVICE WEAPONS USING .30-06

Next Post

100 YEAR HISTORY OF THE .30-06

Next Post
100 YEAR HISTORY OF THE .30-06

100 YEAR HISTORY OF THE .30-06

TRENDING STORIES

  • U.S. NAVY MK18 MOD O CUSTOM CLOSE QUARTER COMBAT WEAPON FOR THE SEAFARING SERVICE

    U.S. NAVY MK18 MOD O CUSTOM CLOSE QUARTER COMBAT WEAPON FOR THE SEAFARING SERVICE

    0 shares
    Share 0 Tweet 0
  • Recreational Use Of 40MM Grenade Launchers

    0 shares
    Share 0 Tweet 0
  • Customizing the Already Custom SIG P320 Spectre Comp

    0 shares
    Share 0 Tweet 0
  • Col. Rex Applegate: The Knife Designs of a Close-Combat Legend

    0 shares
    Share 0 Tweet 0
  • Firearm Review: Pioneer Arms Classic AK in 7.62×39

    0 shares
    Share 0 Tweet 0
  • Trending
  • Comments
  • Latest
U.S. NAVY MK18 MOD O CUSTOM CLOSE QUARTER COMBAT WEAPON FOR THE SEAFARING SERVICE

U.S. NAVY MK18 MOD O CUSTOM CLOSE QUARTER COMBAT WEAPON FOR THE SEAFARING SERVICE

Recreational Use Of 40MM Grenade Launchers

Recreational Use Of 40MM Grenade Launchers

SIG Spectre Comp with AXG Grip Module

Customizing the Already Custom SIG P320 Spectre Comp

Col. Rex Applegate: The Knife Designs of a Close-Combat Legend

Col. Rex Applegate: The Knife Designs of a Close-Combat Legend

New Review: V19N1

New Review: V23N3

SAR|Special

SAR|Special

The Grand Power Q100

The Grand Power Q100

A Fading Star: The star S135 Submachine Gun, That is

A Fading Star: The star S135 Submachine Gun, That is

The Luger Rifle

Where in the world is the Luger rifle?

Book Reviews: September 2016

BOOK REVIEW: Two Great MP40 Books 

Henk Visser Interview: SAR Talks Stoners, CETME, HK with One of the Founders of the Modern Small Arms Industry

Henk Visser Interview: SAR Talks Stoners, CETME, HK with One of the Founders of the Modern Small Arms Industry

The SCCY DVG-1—The Changer of Games

The SCCY DVG-1—The Changer of Games

QUICK LINKS

  • About Chipotle Publishing
  • About Small Arms Review
  • Advertise with Us
  • Write for Us

CONTACT DETAILS

  • Phone: +1 (702) 565-0746
  • E-mail: office@smallarmsreview.com
  • Web: www.chipotlepublishing.com
  • Chipotle Publishing, LLC 631 N. Stephanie St., No. 282, Henderson, NV 89014
Small Arms Review

FOLLOW US

  • Privacy Policy
  • Disclaimer

© 2022 Chipotle Publishing | All Rights Reserved

No Result
View All Result
  • Home
  • Articles
    • Guns & Parts
    • Suppressors
    • Optics & Thermals
    • Ammunition
    • Gear
    • News & Opinion
    • Columns
    • Museums & Factory Tours
    • ID Guides
    • Interviews
    • Event Coverage
    • Articles by Issue
      • Volume 1
      • Volume 2
      • Volume 3
      • Volume 4
      • Volume 5
      • Volume 6
      • Volume 7
      • Volume 8
      • Volume 9
      • Volume 10
      • Volume 11
      • Volume 12
      • Volume 13
      • Volume 14
      • Volume 15
      • Volume 16
      • Volume 17
      • Volume 18
      • Volume 19
      • Volume 20
      • Volume 21
      • Volume 22
      • Volume 23
      • Volume 24
  • The Archive
    • Search The Archive
  • Store
    • Books
    • Back Issues
    • Merchandise
  • Podcast
  • Newsletter
  • Events
  • FrankenGun Challenge
  • About
    • About Small Arms Review
    • About Chipotle Publishing
    • Contact Us
    • Other Publications
      • Small Arms Defense Journal

© 2022 Chipotle Publishing | All Rights Reserved

Welcome Back!

Login to your account below

Forgotten Password?

Retrieve your password

Please enter your username or email address to reset your password.

Log In

Add New Playlist

This website uses cookies. By continuing to use this website you are giving consent to cookies being used. Visit our Privacy and Cookie Policy.

Subscribe To Our Weekly Newsletter

Are you in the know?
Stay up to date with the latest articles.

Facebook-f Linkedin Instagram

Redirecting to External Website

You are leaving the Small Arms Review website and will be redirected to an external link in a 5 Seconds.
VISIT NOW!