The T C Montgomery double barrel shotgun with double barrel hammers is valued at $75 in fait condition. In good condition its valued at $160.
50-100 or so
$700-$3500 depending on condition.
$100 to $250, depending on condition.
It is worth what ever the market will bear.
$500+ depending on condition
gun shop, gun shows, want ads
I have a circa 1874 W.W. Greener double barrel shotgun. It was made in Birmingham England. It has double hammers with nice engraving. Greener shotguns are still produced today but in limited numbers.
Single barrel, under $100. Double-barrel up to $200 unless heavily ornamented.