8x 8 cm (3.1 in) pansarraket m/46 Armour-piercing RP-3 rocket
8x 14.5 cm (5.7 in) Bofors pansarsprängraket m/49A & B High explosive anti-tank (HEAT) rocket
8x 15 cm (5.9 in) sprängraket m/46 High-explosive semi-armour-piercing RP-3 rocket or Bofors sprängraket m/51A & B high-explosive rocket
2x 18 cm (7.1 in) Bofors halvpansarraket m/49A & B Armour-piercing high-explosive anti-ship rocket (later used against general targets.)
1x 250 kg (550 lb) minbomb m/37 general-purpose bomb
1x 250 kg (550 lb) minbomb m/40 general-purpose bomb
1x 250 kg (550 lb) minbomb m/50 general-purpose bomb
1x 500 kg (1,100 lb) minbomb m/41 general-purpose bomb
1x 600 kg (1,300 lb) minbomb m/50 general-purpose bomb
2x vingspetstank drop tanks which could be armed in flight as incendiary bombs, and were tested with napalm.
First production series of fighter version. 54 built between 1945 and 1946, retired in 1949.
Second and third production series of fighter version (62 aircraft each built between 1946 and 1947). Aircraft had better avionics and was armed with a Swedish 20 mm (0.79 in) gun. Retired between 1953 and 1954.
J 21A-3 (later designated A 21A)
First and second production series of attack version (66 aircraft each built between 1947 and 1949). Aircraft was a J 21A-2 equipped with a bomb aiming sight and had pylons for bombs and rockets. It was later upgraded to be able to use two RATO rockets.
Planned version armed with three 20 mm (0.79 in) nose guns, radar in the starboard boom, improved aerodynamics, P-51 style bubble canopy and a stronger engine. Suggested engines were at first the Daimler-Benz DB 605E or the Rolls-Royce Griffon engine but due to the end of the war Germany could not deliver the DB-605E and the British had not yet finished the development of the Griffon engine. It was then decided to use the Swedish DB-605B engine modified to 1700 hp. A full scale mockup was built but due to the jet age the project was scrapped at the end of 1945 due to the Saab 29 project. None built.