No, the draw bolt was used on the Baker line of guns from the first of the hammerless models. It really doesn't have anything to do with the design of the sidelock at all.

The draw bolt is simply a rectangular piece of steel that extends out both sides of the barrel lug and runs perpendicular to the barrels... so looking at the bottom of the barrels the barrel lug and the draw bolt form the shape of a plus (+), but with the draw bolt being smaller in size than the lug. The surface of the draw bolt that faces the breech end of the barrels is tapered slightly. When the barrels are fitted and closed to the action, this draw bolt fits down into a recess in the watertable.

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