The FO had gained a fair few hours on the A300-600 so it wasn't like he wasn't used to the feel of the rudder. Suggesting that the B767 requires more force to swing the rudder from side to side did not have an impact on the FO's reaction in an A300-600 as he had 1) only been flying the A300-600 in his recent career and 2) never flown the 767.