Steven - it comes down to many variables I am afraid , and although I am by no means an expert (plenty are on here though), I have spent some time around some big bores this side of the pond.

More information would be needed on the maker (English?), on the condition, proofing and measurements of the barrels especially, and although the muzzles do not appear in bad shape, it may not be so throughout the remainder of the gun. From the other photos, the wood seems a little worn, but sound and the metal/action fit not bad (although one of the screws seems to bear evidence of some hard work/pressure on it). If you could put up more pictures, you may get some more expert views than mine.

As regards value, it really is a massively wide range; see this

http://www.gunbroker.com/Auction/ViewItem.aspx?Item=184013936

which is a recent example which appears in some worse condition than yours. A well conditioned double 8 with provenance and a strong wildfowling history/maker can often go for >$7-$8k+ or more.

Last edited by CBL1; 08/13/10 06:29 PM.