It is the G.S. Lewis patent action introduced in 12- and 16-gauge as the Riverside Arms Co. No. 315 in the last years of the J. Stevens Arms & Tool Co. After The Great War and Savage Arms Corp.'s acquisition of J. Stevens Arms Co., they introduced a slightly nicer version as the J. Stevens No. 330 and by the early 1920s both guns were offered in 20-gauge as well. Circa 1924-5 they added the .410-bore. In 1928, J. Stevens Arms Co. changed the name of their lower priced line from Riverside Arms Co. to Springfield Arms Co. The J. Stevens No. 330 had a walnut capped full pistol grip stock, while the Riverside/Springfield No. 315 had a walnut checkered half-pistol grip stock. In 1929, J. Stevens Arms Co. introduced a cheaper version of this G.S. Lewis patent double called the Springfield No. 311 with a plain "walnut finished" stock and forearm.
These guns were also made in numerous "Trade Branded" versions up to WW-II. Here is one marked NEWPORT MODEL CN --
