Complex sentence: A cap gun can be disassembled, and a barrel added, turning the toy gun into a real one; a firing pin can then be added to the hammer, to concentrate the force onto the primer of the cartridge.
Split into simpler sentences: A cap gun can be disassembled, and a barrel added, turning the toy gun into a real one. A firing pin can then be added to the hammer, to concentrate the force onto the primer of the cartridge.