These various double guns made by Stevens get confusing, but I'll try to work my way through it.
We need to see a picture of how the pins are arranged in the frame. If the rear pin is higher than the front pin, it is the G.S. Lewis Patent No. 1,136,247, granted Apr.20, 1915. This action used coil-spring driven strickers. This action was introduced on the Riverside Arms Co. No. 315 beginning about 1914, the lower priced line of the J. Stevens Arms & Tool Co. before WW-I. After The Great War, the company emerged as the J. Stevens Arms Co. a wholly owned subsidiary of Savage Arms Corp. About 1923, they began using this action for a slightly nicer gun, the Stevens No. 330. Between 1928 and 29 J. Stevens Arms Co. changed the name of their lower priced line of guns from Riverside to Springfield Arms Co., and the gun became the Springfield No. 315. For 1931, they added a lower priced gun with a plain stock and forearm called the Springfield No. 311. Throughout the 20s and 30s J. Stevens Arms Co. also produced numerous "trade brand" guns on this action like this RANGER --
About 1936 J. Stevens Arms Co. began phasing in a new action with internal hammers rotating about an axle. These have the rear pin lower than the front pin. There were at least three versions of this action -- The No. 330 was replaced by the Stevens No. 530 with the new action usually stamped 5100 on its side;
and the Springfield No. 315 was replaced by the Springfield No. 515 with a version of the new action stamped 5000 on the side.
It seems like they changed slightly what they called these guns each year. In 1937 The No. 515 had double triggers and the No. 515 ST had a non-selective single trigger. For 1940 a No. 5151 had double triggers, and a No. 5151 ST had a non-selective single trigger. In 1940, they introduced a Stevens No. 530M which had the 5100 action with a scallop on the back edge fitted with a stock and forearm made of Tenite.
In 1940 Savage also introduced a more nicely profiled version of this action with some etching, a somewhat nicewalnut stockwith a capped pistol grip and called it the Fox Model B.
As Savage reorganized after WW-II the Tenite stocked 5100 action gun was still a Stevens No. 530M in 1946. Savage turned thier Utica factory over to washing machine production for the post-War housing boom and consolidated the gunmaking at Chicopee Falls. In 1947 the Tenite stocked double was called a Springfield No. 311, and by the 1948 catalogue it was a Stevens No. 311, while the gun with a checkered walnut stock remained a Stevens 530. The Tenite stock was gone with the 1952 Savage/Stevens/Fox catalogue and the Stevens Model 311 had a walnut finished hardwood stock and forearm. The Stevens Model 530 was last in the 1953 Savage/Stevens/Fox catalogue, and from 1954 on there was just the Stevens Model 311 and variations of the Fox Model B.
