Try e-gunparts.com. Cost will exceed the value of the weapon.
It should only cost a few dollars if it only needs the firing pin replaced. Your shotgun is only worth $50-$75 as a shooter (but have the gunsmith verify that it is safe) and about the same as a decorator (wouldn't need the firing pin anyway). So, economically, it's probably not worth the expense.
Needs to be evaluated by a GOOD gunsmith.
Does it need to be cleaned and regapped? Maybe it needs to be replaced?
Needs to be examined by a gunsmith.
It should engage on firing. Not dry firing, but firing with a loaded shell. If it does not, it needs to go back to the maker, or to a repair shop.
Since we have no information on what needs fixing, the answer is take it to a gunsmith.
Needs to be checked out by a gunsmith.
It needs to be looked at by a gunsmith
A shotgun needs wadding to prevent air or gas from leaking out. If the gas leaks out the gun has no compression meaning the ammunition won't go very far.
Needs to be inspected by a good gunsmith.
Needs to be examined by a good gunsmith
can you give the age of a double barrel shotgun made by Seminole? 20s 30s i got a double barrel that needs a stock and forarm.know where i can get one?