HI,
I agree with Feltwad. My references (in this case Blackmore and, Bailey and Nie) show a Joseph Hunt as a Birmingham maker 1766-1774 but also a contractor to ordnance 1774-1782 and the East India Company 1774). As Feltwad mentioned, the lock certainly could be from that time period. The acorn finial on the trigger guard suggests the period 1760-1790 and so does the butt plate. However, to me, the stock shape and style of checkering seems later, more like the end of the 18th or early 19th centuries. I wonder if it was restocked or made new then but used older salvaged or left over parts.
dave