 Armament was two Nudelman N-37 37-mm cannon located in the leading edge of the aircraft's wings, near the wing roots - the guns had been moved compared to those in the MiG-15 and -17 to avoid ingestion of gun blast gases causing surging of the aircraft's engines.The first SM-2, the SM-2/1 was sent to the "Letno-Issledovatel'skiy Institut" (en