The HK93 is the semiautomatic civilian version of the HK33 Rifle imported into the United States between 1975 and 1989 (the year that all 'evil' looking rifles were in essence barred from import without some modifications). It is actually an updated version of the Civilian HK43 Rifle (which was the semi auto sporting rifle variant of the HK33 imported 1974.). It differs from the select fire HK33 by way of a metal trigger pack, no push pin assembly and no paddle release as well as the single "0" and "1" fire select settings (indicating it is a Semi Auto only rifle).
The HK33 reduced to the size of a Heckler & Koch MP5 to make it a Personal Defense Weapon (PDW). It is used by some military units or SWAT teams when both the power of a rifle and the compactness of a submachine gun is needed.
Developed in the 1980's, the G41 is an HK33 modified to STANAG standards. Besides having a uniquely-attached "burst" trigger group (Safe-Semi-3 round burst-Auto), the G41 could take M16 magazines. What killed the design was its outrageous price of $1,700 per weapon for law enforcement in 1980's dollars.