Viper Skiffle Group's "The Wild Colonial Boy"

I'm not sure if I noticed this before or not, but I certainly haven't written about it.  In Viper Skiffle Group's "The Wild Colonial Boy," there's an interruption in the drum part in the middle of the lines "Well, he fired a shot at Kelly" and "Then he fired a shot at Fitzroy too."  Throughout the verses, there's a kind of shuffle that I think is played with brushes, but after the "fired a shot" phrases, there's a sudden hit, apparently to portray those shots.