page_title: Wheellock
section_title: Preparing to fire
hierarchical_section_title: Wheellock / Design / Preparing to fire
caption_attribution_description: The exterior of a wheellock mechanism from a "puffer" or pistol of about 1580 (photo reversed).
context_page_description: A wheellock, wheel-lock or wheel lock, is a friction-wheel mechanism to cause a spark for firing a firearm. It was the next major development in firearms technology after the matchlock and the first self-igniting firearm. Its name is from its rotating steel wheel to provide ignition. Developed in Europe around 1500, it was used alongside the matchlock and was later superseded by the snaplock, the snaphance and the flintlock.
context_section_description: First, the dog is rotated forward to the "safe" position, and the priming pan pushed open (if it is not already so). After loading a powder charge and ball through the muzzle in the usual way, the operator takes his "spanner", slips it on to the square section of the wheel shaft, and turns it until a click is heard (about one half to three-quarters of a revolution), and the wheel is felt to lock in place, whereupon the spanner is withdrawn. What occurs is that when the wheel is turned, the mainspring is tensioned via the chain, which is wound partially around the shaft. The click is the sound of one end of the sear engaging in the blind hole on the inside of the wheel, thus immobilising it.
  The pan is then primed with powder, and the pan cover pulled shut. Finally the dog is pulled back so that the pyrite in its jaws is resting on the top of the pan cover, under some pressure from the spring at the toe of its arm.
caption: The exterior of a wheellock mechanism from a "puffer" or pistol made in Augsburg in about 1580. The photo has been reversed in order to facilitate comparison with the interior view below.
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