When did the Mk IIa series 1 Hurricanes first enter service ?
Hurricane Mk IV The last major change to the Hurricane was the introduction of the " universal Wing " , a single design able to mount two 250 lb or 500 lb ( 110 or 230 kg ) bombs , two 40 mm ( 1.57 in ) Vickers S guns , drop tanks or eight " 60 pounder " RP-3 rockets .