Dear John,

Thank you for contacting Mearto with your appraisal inquiry. My sincere apologies for the delay with the appraisal.

The presented object appears to be a flintlock blunderbuss made in the last third of the 18th century or early 19th century. The stock has engraved brass fittings and a plaque with a monogram. This is probably the monogram of the former owner. Gunsmiths stamp or engrave their pieces usually on the lockplate or the barrel.
Comparable objects were recently offered and sold on the international auction market.
This piece is in good condition and no severe damage is visible in the images provided.
A fair market estimation would be between 1500 to 2500 USD.
This estimate is based on actual recent past recorded auction sales of comparable items. Retail "asking prices" can be higher and may vary.

With kind regards,
George