Steyr-Solothurn S1-100 Gun Review - steyr-Solothurn S1-100 (Austria - SMG - 9 mm Parabellum) Review What is your rating of the Steyr-Solothurn S1-100 ? Feel free to compare the Steyr-Solothurn S1-100 to similar types of guns / firearms. Politics, Business, Civil & History.