Abstract: A tool is provided with a barrel having a piston for driving a fastener into a substrate, the barrel being mounted for axial movement within a body of the tool and a nose piece being mounted forwardly of the barrel and being at least partially encapsulated by a base plate that connects to the receiver of the tool which encloses the barrel and piston, the present invention permiting ease of assembly and disassembly of the muzzle of the tool—the nose piece and base plate—by making the connection between the base plate and the receiver with a retainer element.