HK SMG II - Not a tremendous amount of information is available about the submachine guns that were designed
          and built in the 1980s as attempts to improve the MP5.  The SMG I, the SMG II, MP2000 and
          MP5-PIP are designs that became functioning firearms, but never reached full production status.   All
          but the MP5-PIP and the MP2000 included a valve that was just forward of the magazine for the
          selection of super or subsonic ammunition.  All of these prototypes with the exception of the
          MP5-PIP were designed with integral suppressors.  The SMG I and II are covered here.

          The SMG I was designed in 1981 for the United States Navy under the JSSAP (Joint Services Small
          Arms Program) Advanced 9mm Submachine Gun program.

          The SMG II was designed in 1984.  The primary difference between the SMG I and II is the rear
          sight.  The SMG I had the rear sight similar to the HK21 series.  The SMG II was similar to the MP5
          series.

          It quickly became apparent to the Armed Forces that improving on the MP5 would be difficult. 
          These guns were abandoned in favor of the MP5-N, a standard MP5 with threaded barrel, tritium
          front sight, retractable stock and ambidextrous trigger group.  This model continues to serve with
          distinction, and has a national stock number as well