 The flame from the burning of the gunpowder propellant ignited this "fuze" on firing, and burned through to the centre during flight, then igniting or exploding whatever the projectile may have been filled with.By the 19th century devices more recognisable as modern artillery "fuzes" were being made of carefully selected wood and trimmed to burn for a predictable time after firing.These were still typically fired from smoothbore muzzle-loaders with a relatively large gap between the shell and barrel, and still relied on flame from the gunpowder propellant charge escaping past the shell on firing to ignite the wood fuze and hence initiate the timer.