Joe,
I tend to agree with you on this one.
overlooking the various parts, it sits with me as about 1790, but using or re- using some earlier parts.
I have a Twigg single sporting gun, altered to percussion, and enough breech end of the barrel removed so that half of the Twigg mark below the barrel is missing. It is obviously a decent conversion, but not best, and the gun was re-stocked using the original furniture.
To me it was a cheaper way of modernizing a gun into something useful for say a gamekeeper. decent, competent, but not the best work.
There must have been thousands of guns brought up to date or re-stocked for various reasons, and given to employees to use.
The short wrist and plainness of the gun in the OP, says it fits into this category.
I also have one incredibly bad relic, out of Ireland, it is stocked up in roughly 1790 sporting gun fashion, but the parts are India Pattern brown Bess, with the guard simplified. The woodworm had eaten most of the stock, but enough remained to say a re-stock.
Re age,
In GBG 1540 to 1740, Keith Niel says regarding the charming charecatures seen on the wrist on earlier pieces, that this was a short lived fashion, that ended before 1700, or roughly 1675 to 1690's.
I have John Hall blunderbuss , which must date to the 1740's yet has all the early characteristics, including this charecature. (spelling!)
40 to 50 years out of date when made?
Never and always are poor words at the best of times!
Best,
R.