http://www.guntrader.co.uk/Guns-For-Sal ... 2122108545
The seller has this to say about the gun
Rare scottish 13-bore pinfire by John Lyell of Aberdeen. This gun has the rare W.J.Harvey patent sliding barrel system. The gun is opened by a hinged underlever sliding the barrels forward for loading! There are holes in the nose of each hammer so after firing and sliding the barrels forward the holes engage with the pins to extract cartridges. The stock is of high quality walnut with delightful hand chequering on the grip and fore-end LOP 141/2". This gun is of the highest quality.
Best-
Vikram