British and Continental gun values can be estimated by estimating Brand Value level (BV), Original Quality grade (OQ), and Current Condition level. Powell is Brand Value level two (BV2), which will give a value 3/4 of a similar gun with a BV1 (Boss, H&H, Purdey, and Woodward) name. The OQ sounds like somewhere in the OQ1.5 (not quite a best work gun) to OQ2.5 (about mid-point in quality for sle guns). Dig is right in that OQ will have the most impact on this estimate as it is hard to estimate from the description. The CC sounds much like CC3 (Significent use) to CC4 (Heavy use, but no abuse
).
BV2-OQ1.5-CC3 = $13400, BV2-OQ2-CC3 = $11000, BV2-OQ2.5-CC3 = $9700, BV2-OQ1.5-CC4 = $10400, BV2-OQ2-CC4 = $8300, and BV2-OQ2.5-CC4 = $7300. If the gun turned out to be a restored "B" grade (BV2-OQ3-CC5) the value should be about $4700.
The foregoing is based on analysis of a bunch of auction results. Hope this helps some.
