John here.....question for the RAF folks here...hope this is the right place. Was watching the History Channel today and the episode was concerning Douglas Bader and the Spitfire...My question is :there are 2 tube-like projections, one on each wing....are those the machine gun barrels and if so why only 2?..American fighters had multiple barrels(that were flush w/leading edge)....What size guns were on the Spit? Thanks in advance...John