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
  • Podcasts
  • Newsletter
  • Events
  • 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
  • Podcasts
  • Newsletter
  • Events
  • About
    • About Small Arms Review
    • About Chipotle Publishing
    • Contact Us
    • Other Publications
      • Small Arms Defense Journal
Search
Results for {phrase} ({results_count} of {results_count_total})
Displaying {results_count} results of {results_count_total}
Generic filters
Search
Results for {phrase} ({results_count} of {results_count_total})
Displaying {results_count} results of {results_count_total}
Generic filters
Small Arms Review
Home Articles

Revisiting the SPIW Part Three

SAR Staff by SAR Staff
August 2, 2022
in Articles, Articles by Issue, Guns & Parts, Search by Issue, V19N3 (Apr 2015), Volume 19
Revisiting the SPIW Part Three
Share on FacebookShare on Twitter

The AAI ACR, a modified version of the previous AAI SBR rifle, as it appeared in the ACR field experiment. This rifle fired a 5.56x45mm subcaliber flechette round at 4,600 fps, at a cyclic rate of 1,800 rpm in the three-round burst mode. (U.S. Army)

By R. Blake Stevens

“Reorienting” the SPIW and Adopting the XM16E1

Again, as had been the case in 1964, the most charitable conclusion after the second generation SPIW trials was that neither of the “weapon concepts” was acceptable in its present state. The AAI SPIW was chosen as the better of the two: hardly a choice at all in view of the enforced termination of the Springfield program and the lack of any immediate civilian interest in its continuance.

Early in the fittingly gray month of November, 1966, the Infantry Board formally recommended to the Chief of Staff of the Army that the whole SPIW program be radically pruned back and relegated to the status of an exploratory program at AAI.

On November 7, the Office of the Chief of Staff accordingly directed that the SPIW program be “reoriented” from full-scale engineering development back to exploratory development, becoming in the process just one facet of a broadened, long-term small arms R&D program for the future. The same memorandum announced the formal intention to adopt the Colt XM16E1 rifle as standard for the U.S. Army everywhere but in the European theater.

With the Army having thus come full circle and now solidly behind the M16, the pressing need for the SPIW simply vanished. For the SPIW itself, the collapse of the second generation program marked the end of the lavishly-funded grande époque, the likes of which would never be seen again.

Lineup of cartridges that featured in the ACR field experiment. From left: 5.56mm M855 ball, 5.56mm loaded with Olin yellow-tip Duplex, AAI saboted flechette in 5.56mm case, Steyr-Mannlicher plastic-cased flechette with ring primer and H&K 4.92mm caseless cartridge. (U.S. Army)

The AAI XM19 Serial Flechette Rifle (SFR)

Nevertheless, development continued at AAI over the next few years, funded largely from within the company. This led to a heady but temporary resurgence of interest in the flechette-firing SPIW.

The Army had seized on the limited but encouraging success of AAI’s 1967 nominal-fee contract modifications, authorizing an additional $500,000 in fiscal 1968 to step up produceability studies on flechette ammunition.

The Army’s new four-phase serial flechette rifle (SFR) contract with AAI became a reality in October, 1968. A field experiment had already been tentatively scheduled for April, 1970, wherein the new SPIW would be compared with the M16A1 under simulated combat conditions.

HQ Army Weapons Command (now called WECOM) publicly confirmed the awarding of the letter contract to AAI on January 21, 1969, “for continued development of the Special Purpose Individual Weapon (SPIW) and its associated ammunition.” A scant six months later in June, WECOM announced that the phase-two prototypes, now officially called the “XM19 Rifle, 5.6mm, Primer Activated, Flechette Firing,” were under construction. This first bestowal of an official “XM” number on a SPIW candidate was an important and long-awaited honor: it signified formal recognition that the SPIW had advanced one indispensable step closer to becoming the Army’s next rifle system.

Right side of an AAI XM19 Serial Flechette Rifle (SFR), reconfigured to accommodate a 50-round box magazine. Both this and the single-shot grenade launcher represented a relaxation of the long-held specifications for 60 rounds of point-target and 3 rounds of area-target ammunition, which had been a major stumbling block throughout the entire SPIW program. Weight in this configuration: 7 lbs; maxim

Calling the SPIW to Account

If anything could have saved the SPIW program it was AAI’s improved XM19 rifle and its later, short-lived follow-on, the XM70, which fired from the open bolt. However, to an increasing number of observers, both in and outside the program, the curious and continued determination to ignore the fundamental gulf between the SFR (SPIW) requirements and the real world needed to be addressed. On July 30, 1969, Congressman Richard L. Ottinger of the House of Representatives wrote a formal letter to the Comptroller General of the United States. By this time, some aspects of the Future Rifle Program were already under investigation by the U.S. General Accounting Office (GAO). An excerpt from Mr. Ottinger’s letter reads as follows:

… I am writing in regard to the Special Purpose Individual Weapon (SPIW) currently being developed by the AAI Corporation for the Department of the Army… It is my understanding that after seven years of research and development and the expenditure of some $20 million, the SPIW is still not ready for production and use. I further understand that some five different engineering deficiencies have been identified and that it is anticipated that some additional 12 to 18 months will be necessary to correct these deficiencies.

I would appreciate your advising me as to how much more it will cost to correct the five present deficiencies and whether any additional research and development funds will be spent; why is this weapon being developed in the first place, [and] when will the SPIW be ready for use by our Armed Forces personnel?

A diagrammatic sectioned view of the 5.56mm Colt/Olin Duplex cartridge as used in the ACR field experiment, fitted with two full-caliber armor-piercing projectiles with hardened steel cores, loaded in the standard M855 case. Maximum effective range was 325 meters. (U.S. Army drawing)

The XM19 is Snatched from Near Perfection

Ironically, it appears that by this time the AAI weapon was virtually at the point of perfection, and yet as the XM19 neared this tantalizing goal its detractors gained in voice and power, and the mood of good fortune, which had begun in 1967, began to slip away, never to return.

Withdrawal from Vietnam Pulls the Plug on the SPIW

In the midst of all these acrimonious thrusts and investigations, the 1973 end of the American military presence in Vietnam effectively “pulled the plug” on any urgent, large-scale development plan for a new U.S. individual weapon. Small arms research, development and engineering (RD&E) money dried up abruptly, adding an indisputable air of finality to the last SPIW developments. As stated in the Research, Development and Engineering (RD&E) Laboratory Posture Report for fiscal 1974, prepared by Army Armament Command at Rock Island:

… In December 1973, the decision was made to remove flechette ammunition from immediate consideration within the FRS (Future Rifle Systems) Program because of technical problems which may not be correctable in the time frame of the future rifle…

A diagrammatic sectioned view of the AAI saboted flechette, as loaded in the standard 5.56mm M855 case. (U.S. Army drawing)

Summing Up the Failed SPIW Program

The point target portion of the AAI SPIW was designed to fire controlled bursts of 10-grain flechettes at 2,400 rpm, thus taking advantage of the flechette’s minimal recoil to achieve a deadly, ultra-tight mean burst spread. As regards the crucial characteristic of recoil impulse, the 10-grain flechette still reigns supreme, far superior to the M16 on full-automatic fire. As recorded in The Black Rifle, a comparison prepared by the Human Engineering Labs (HEL) at Frankford Arsenal showing the typical recoil impulse of several standard weapons reads as follows:

7.62mm NATO M14: 2.65 lb. sec.
.30 M2 Carbine: 1.18 lb. sec.
5.56mm M16 (w/muzzle brake): 1.16 lb. sec.
AAI SPIW (no muzzle brake): 0.65 lb. sec.
AAI SPIW (w/muzzle brake): 0.39 lb. sec.

For such a light projectile to be lethal, however, a muzzle velocity in the order of 4,800 fps was required. This in turn necessitated a chamber pressure approaching 70,000 psi.

In the frantic attempt to perfect weapons capable of attaining these pressures and velocities, many frontiers of knowledge had to be pushed back, all at the same time. This in turn uncovered a veritable host of new technological problems that could not possibly have been foreseen and which, ironically, were misconstrued as poor engineering. It was the previously unheard-of magnitude of these new problems – heat; erosion; muzzle blast; component overstressing and flechette cartridge complexity – which ultimately proved insurmountable within the overall timing and funding constraints set for the program.

Right side view of the “early finalized” version of the Colt ACR, showing the optional carrying handle with iron sight, top left, and the ELCAN 3.5X telescopic sight, either of which could be attached to the rail on the flat-topped receiver. The Colt ACR action was mechanically identical to that of the M16A2. The rate of fire was 624 rpm when firing the yellow-tipped Colt/Olin Duplex round, and 66

A Brief Reprieve – in the ACR Program

The following is excerpted from the Collector Grade title Black Rifle II, written by Christopher R. Bartocci and published in 2004 as a follow-on to The Black Rifle, which had covered the early history of the M16 up to the time of its publication in 1987.

We begin with an overview of, and rationale for, the Advanced Combat Rifle (ACR) program from Black Rifle II, as follows:

Throughout the last half of the twentieth century, the U.S. Department of Defense initiated several programs aimed at replacing the M16 series rifles altogether with a new design.

When the AR-15/M16 was first adopted during the early 1960s, it was considered merely an interim weapon while development of the futuristic, flechette- and grenade-firing Special Purpose Individual Weapon (SPIW) was under way. At that time it was confidently predicted that the SPIW would be classified “Standard A” by June of 1965. Despite a great deal of costly effort, however, the SPIW concept was never perfected.

Twenty years later, during the period 1986 to 1990, the Department of the Army tried again, by funding the Advanced Combat Rifle (ACR) program.

It had been a hard but valuable lesson to learn that, due to the high levels of stress, fatigue and fear experienced during actual combat engagements, soldiers will not shoot as well as they were trained to shoot. The objective of the ACR program was to replace the M16A1, and the then newly-adopted M16A2, with a new rifle, which would increase both hit probability and combat effectiveness by 100%.

Excerpts from a voluminous retrospective prepared by the Army Research, Development and Engineering Center (ARDEC) at Picatinny Arsenal titled ACR Program Summary read as follows:

“The ACR Operational and Organizational Plan (O&O) was approved in January, 1985 [which] caused weapon concepts to be developed under contract and prototype hardware to be produced and evaluated with troops in a field experiment.

“In September 1982 contracts were awarded to AAI Corporation and Heckler & Koch, Inc.
“In 1984 – 1985, industry conferences were held at ARDEC and Fort Benning. Shortly thereafter, contracts were competitively awarded to AAI, ARES, Colt, McDonnell Douglas, and Steyr [calling] for the development and fabrication of the proposed rifle systems for evaluation in government tests. Both the ARES and McDonnell Douglas contracts were terminated before the final ACR field experiment took place, due to “lack of maturity” of their systems.”

A diagrammatic sectioned view of the Steyr-Mannlicher saboted flechette fully telescoped within a plastic case fitted with a ring primer. (U.S. Army drawing)

The AAI ACR

“AAI was the repository of the equipment necessary to produce the flechettes needed for both their contract and the Steyr-Mannlicher contract. The production of flechettes was a cost, time and quality problem throughout the entire development effort. There is some controversy as to whether the flechette round is inherently less accurate and whether any amount of future development effort would result in equal accuracy to a standard bulleted round. The pace of technology today is such that it is unlikely that further development work on small-caliber flechettes will be funded for rifles.

“The AAI weapon is a 5.56mm modified version of the previously developed Serial Bullet Rifle (SBR) using a reciprocating bolt mechanism.

“The AAI round uses the standard 5.56mm M855 brass case with M41 primer. The projectile is a 10.2 grain sub-caliber flechette. The sabot is a liquid crystal polymeric compound (plastic), which is designed in four segments held together by a neoprene “O” ring at the rearmost point of the sabot segments.”

The Steyr ACR

“The Steyr system was similar to the ARES system in that it fired using a rising chamber mechanism. However the Steyr ACR fired a single flechette from a plastic case using a radial ring primer. Initiation of the ring primer was from the side of the case near the base.

“The Steyr gun is a true open-bolt mechanism in that there is a spent case normally in the chamber in the out-of-battery condition. A live round only enters the chamber after the trigger has been pulled.

An inherent drawback to the Steyr system lies in sabot hazard to friendly troops. This is a safety concern that exists in the AAI system as well.

The Colt ACR

The Colt ACR was essentially a product-improved M16A2, painstakingly modified to meet the criteria of increased hit probability and combat effectiveness. It was fitted with a new hydraulic buffer, a modified pistol grip, a flat-top receiver with an integrated rail, capable of accepting a detachable carrying handle embodying the A2-style adjustable rear iron sight or the ELCAN (Ernst Leitz, Canada) optical sight, plus a heightened sighting rib proposed by the Army HEL (Human Engineering Laboratory) mounted on a semi-beavertail handguard, and a proprietary muzzle brake/compensator designed by Knight’s Armament Co.

The Steyr-Mannlicher bullpup ACR entry, firing a plastic-cased subcaliber flechette at a salvo rate of 1,200 rpm. (U.S. Army)

Conclusions of the ACR Program -Reaffirming the M16A2

None of the ACR contenders emerged as a replacement for the existing arsenal of conventional rifles. However, the unprecedentedly sophisticated data collection systems developed for the program, which included the ability to not only record hits but to actually measure the amount by which a shot missed the target as well, led to some highly encouraging conclusions regarding the ACR contenders, plus an upwardly revised opinion of both the M16A2 and the soldiers who participated in the program. The following is a further excerpt from the ACR Program Summary:

… The baseline performance of the M16A2 rifle was better than anticipated in terms of hit probability… No rifles showed a n increase in probability of hit over the M16A2 under the stressed conditions of the test.

The feasibility of caseless and lightweight plastic-cased ammunition has more than been demonstrated in this program. Few problems were experienced with the [H&K] caseless rifles in the test. The past technical barriers of cook-off and vulnerability have now been overcome…

The End of the Road (So Far) for the Serial Flechette

A final excerpt from the ARDEC ACR Program Summary reads as follows:

… Many advances in high-performance rifle flechette technology have been made during this effort. New engineering plastics and sabot designs have solved previous launch reliability problems.
Although significant advances were made in reducing flechette round-to-round dispersion, the dispersion of flechettes is still greater than that of bullets. It is unlikely that the round-to-round dispersion will be reduced further, which would likely preclude flechettes from further consideration as single shot rifle projectiles.

[However,] their high cross-sectional energy density and large length-to-diameter ratio make them very effective against all small arms targets. This, together with their flat trajectory and short time of flight, make them attractive for consideration in crew-served and area-fire applications…

This article first appeared in Small Arms Review V19N3 (April 2015)
and was posted online on February 20, 2015

Author

  • SAR Staff

    View all posts

Tags: 2015AAIACRApril 2015PART IIIR. Blake StevensSPIWV19N3XM16E1
Previous Post

Trials With Rifle Grenade Launchers For The German Paratrooper Rifle FG42

Next Post

Rock River Arms LAR 47 AR: AR chambered in 7.62×39 using AK47 magazines

Next Post
Rock River Arms LAR 47 AR: AR chambered in 7.62×39 using AK47 magazines

Rock River Arms LAR 47 AR: AR chambered in 7.62x39 using AK47 magazines

TRENDING STORIES

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

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

    0 shares
    Share 0 Tweet 0
  • Perfecting the Israeli Krinkov – Krebs Custom Galil ACE 5.45x39mm Pistol

    0 shares
    Share 0 Tweet 0
  • H&K LOWER ID GUIDE

    0 shares
    Share 0 Tweet 0
  • Evolution of the U.S. Grenade Launcher From World War II to Today’s Conflicts

    0 shares
    Share 0 Tweet 0
  • MP5 CLONE FROM LSC FLAT

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

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

Krebs Custom Galil ACE 5.45x39mm Pistol

Perfecting the Israeli Krinkov – Krebs Custom Galil ACE 5.45x39mm Pistol

H&K LOWER ID GUIDE

H&K LOWER ID GUIDE

Evolution of the U.S. Grenade Launcher From World War II to Today’s Conflicts

Evolution of the U.S. Grenade Launcher From World War II to Today’s Conflicts

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

5.11 Promotional Image

New 5.11 Products for Spring / Summer 2022

Mesa Precision Arms: Drop the Weight, Get the Game

Mesa Precision Arms: Drop the Weight, Get the Game

U.S. Capitol Building at night

ATF’s New “Frame or Receiver” Rule: What You Should Know

NICS Denial Notification Act to Require FFLs Provide Buyer Address

NICS Denial Notification Act to Require FFLs Provide Buyer Address

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

Search
Results for {phrase} ({results_count} of {results_count_total})
Displaying {results_count} results of {results_count_total}
Generic filters
  • 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
  • Podcasts
  • Newsletter
  • Events
  • 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

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!