a) What is it? - sig 551 swat, made for cops.
b) What happens when it goes bang,as it appears to be forward of his shoulder? - bog all if he did fire it, 5.56mm has little recoil, that 'pose' is used by many for just having a butchers through the scope.
c) Is it a recoiless job? - no.
So many questions,so little time! - .its good to have a full day.