Board Thread:Off Topic/@comment-27425734-20170826213348/@comment-28342756-20170923085752

If I were capable of drawing adequately, I'd be able to show how the insides of the barrel work [a cut-out of Quatern]. The barrel is bigger than it appears, and the blade is slightly bigger than that of a rapier (but is a rather small, narrow sword). As such, the barrel has a cylinder within it, where each round is fired from. In between it and the 'skin' of the gun, is room for the blade to retract into.

In short, there's room within the enlarged barrel for the firing cylinder and thin blade.