I believe the Thompson Contender could be found in .410. There was a company from Argentina which manufactured a single shot pistol which, by replacing the choke, could fire either a .45 Long Colt round or .410 shotgun shell. As far as I know, they're no longer in business, and you'd have to search for one which was for sale.. offhand, I'd recommend Gun Broker, Auction Arms, and Guns America. You'd have to buy it there, and have it shipped to an FFL for receiving.
If this is a Stevens single shot #35 in .410. It is on the Federal List of banned weapons and is illegal to possess, or sell. Look at the National Firearms Act.
Never heard of it. Need a detalied description of all markings, finish, barrel length, condition. Leinad made several different models of .410/45LC derringers. A five shot pepperbox, single shot pistols, double barrel pistols, and a Model PD which was a two shot revolving pistol.
Try Taurus
1875
Local gun shop, local gun show, for sale ads, Shotgun News, Gun List will get you started.
Yes, it is a 410/45LC combo derringer, and runs about $80-$100.
Depends on whether it is an NFA item or a C&R
No.
50-100
winchester 1n 1875
priceless
About $50-$75