Yeah there is. The chest / barrel piece just snaps off as there is a clip holding it in place. Inside there are two small screws that when removed the whole chest / waist piece (everything above the grey trigger piece) comes off.
The reason why it all comes apart is because it was the housing for the spring mechanism which was removed for the Australian release of the toy.
I've performed this operation with success after I had to replace Megs entire chest.