Also known as the WAC-021, this 155 mm howitzer is used by the Iranian army as towed artillery. Built to fire NATO-compatible ammunition, it was originally designed and built in China by the NORINCO corporation. It is one of the newest artillery pieces fielded by Iran and comes with a pivot so the weapon can be rapidly relaid.
The WAC-21 is very similar in many respects to the Austrian NORICUM GH N-45 gun-howitzer, to the extent that the carriage of the Type WA-021 can accommodate the ordnance of the NORICUM weapon. The NORINCO Type WA-021 has an auto-frettaged barrel 45 calibres long, fitted with a multibaffle muzzle brake, which has an efficiency of 30 percent. A screw-type breech mechanism opening to the right is employed and the chamber volume is 22.95 litres. The rifling employs 48 grooves with a twist of 1 in 20 calibres, and the grooves are understood to be three times deeper than the rifling depths found on comparable Western 155 mm designs.