One of the noted rarities among 19th century American firearms will be on offer in Lancashire on August 30 when Silverwoods of Clitheroe sell this John Walch Navy Model 12-shot percussion revolver.

This strange hybrid aimed to increase the number of rounds that could be fired from a normal six-shot revolver by double-charging the chambers, each of which is fitted with two sets of nipples fired by twin hammers and twin triggers.

In practice this complicated arrangement was not popular and only around 200 were made between 1859 and 1862.

This example has the serial number 20 and an assembly number 138. It is estimated at £7000-10,000.

Contact: 01200 423322.