6 2 ▁AA ▁B de , ▁which ▁was ▁engaged ▁in ▁air field ▁defence ▁for ▁Fif th ▁US ▁Army . ▁Once ▁Fif th ▁Army ▁had ▁captured ▁Rome ▁in ▁June ▁ 1 9 4 4 ▁ 1 2 ▁AA ▁B de ▁deployed ▁its ▁units ▁to ▁defend ▁the ▁brid ges ▁over ▁the ▁T iber ▁and ▁the ▁port ▁of ▁Pi omb ino . ▁Then ▁when ▁rel ieved ▁it ▁was ▁able ▁to ▁follow ▁close ▁behind ▁Fif th ▁Army . ▁Although ▁the ▁Luft wa ffe ' s ▁losses ▁meant ▁the ▁air ▁threat ▁was ▁lower ed , ▁H AA ▁batter ies ▁of ▁ 6 2 ▁AA ▁B de ▁also ▁employed ▁their ▁vers atile ▁long - range ▁ 3 . 7 - inch ▁guns ▁in ▁a ▁medium ▁art illery ▁role ▁against ▁ground ▁targets . ▁This ▁included ▁counter - b atter y ▁( CB ), ▁def ensive ▁fire ▁( DF ) ▁and ▁har ass ing ▁fire ▁( H F ) ▁sho ots , ▁but ▁also ▁air - bur st ▁sho ots ▁against ▁ent rench ed ▁positions , ▁and ▁destruction ▁of ▁hard ▁targets ▁such ▁as ▁buildings . ▁ ▁Once ▁Fif th ▁Army ▁had ▁crossed ▁the ▁Ar no , ▁it ▁faced ▁the ▁Ser chio ▁and ▁the ▁def ences ▁of ▁the ▁Goth ic ▁Line . ▁On ▁ 2 6 ▁December ▁the ▁German ▁forces ▁put ▁in ▁a ▁major ▁counter att ack , ▁Unternehmen ▁Winter gew itter ▁( Operation ▁Winter ▁Storm ), ▁between ▁Lu cca ▁and ▁P isto ia ▁aim ed ▁at ▁ret aking ▁the ▁port ▁of ▁Liv orno ▁( Leg horn ). ▁ 6 2 ▁AA