Diamond Arms Company and Nitro King are both trade name used by the Shapleigh Hardware Company of St. Louis, Missouri. Some of the guns were imported from various Belgian sources, but they were also made by W.H.Davenport Firearms Co (1890's - ), Iver Johnson Arms & Cycle Works (early 1900's - ), J. Stevens Arms (before 1942), and Savage Arms. If there is an oval with ELG* stamped on the barrel or action, it is from Belgium, but being a 410 makes that unlikely. That also eliminates Davenport as the maker.
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You have already identified it as a Shapleigh's King Nitro. Shapleigh Hardware was in St Louis Missouri from the mid 19th century until the middle of the 20th. Their King Nitro guns were manufactured by W.H. Davenport and later by Stevens/Savage.
Both 'King Nitro' and 'Central Arms Co' are trademarks of the Shapleigh Hardware Co, which was a major catalog retailer from the late 1800's well into the 20th century. The shotguns marketed under that name were made for Shapleigh by different companies, notably Davenport Firearms, Crescent, Hopkins & Allen, and Stevens. We'd have to see the shotgun to determine which manufacturer actually made the shotgun. www.countrygunsmith.net
I believe that King Nitro was a model name of Shapleigh Arms Co, St. Louis, MO.
no answer but i have a king nitro 22. long rifle used in WWI/WWII has no information it took quite a hit in the chamber though it was handed down to me from my great grandfather.
25-100 USD
There were many thousands of the Shapleigh King Nitro 16 Gauge with a double barrel. For the most part, they are worth about $50 to $100 depending on mechanical and finish condition.
King Nitro was a trade name used by Shapleigh Hardware of St Louise on guns made by Crescent Firearms and J. Stevens Arms.
They were made for the Shapleigh hardware store chain roughly 1920-s-early 1940s.
The 12 gauge King Nitro number 3411 is likely a vintage shotgun manufactured by King Nitro. It may have a 2 3/4" chamber and be of good quality, but specific details about its features and history would require further research or inspection by a gun expert.
nitro hunter shotgun single barrel with exposed hammer stamped belknap hdwre and mfg serial 5516
Proofhouse.com has a store brand chart that might help.