I recently purchased a Sterling Arms X-caliber .44 mag single shot pistol (kinda looks like a Thompson Contender but with wooden grips). Gundealers I spoke with told me little but that Sterling is a low end gun, but I found out that they were all talking about semi-autos. This is a very hard company to resaerch on. So I began posting questions on other sites and finally one man who owned two X-calibers gave me his exhausted reseach on Sterling Arms, for anyone who' s clueless on Sterling I hope this helps!

A little more about Sterling Arms and E & R Machine:
E7R Machine Inc. was incorporated in the state of New York in April of 1961 with Eugene Sauls as President and Robert Lindke as Treasurer, each owning 50% of the company. The company' s first place of business was a small 900 sq ft building in Lockport, NY. By 1963, the business had outgrown the original building and they rented 5,000 sq ft of floor area in Gasport, NY. (not in Calif.) Their business continued to grow and late in 1971, they contacted Sterling Arms in Buffalo, NY, about becoming the licensed manufacturer of their products. Sterling had been in business about three years and were having trouble with machining. E & R set up a plant at 4436 Prospect Street, Gasport, NY, to handle the manufacture of firearms for Sterling in `1972. In December of 1973, E & R purchased all the stock of Sterling Arms Corp. making Sterling a wholly owned subsidiary of E & R. In 1975, Eugene E. Sauls, President, bought the 50% ownership of Robert Lindke and became sole owner of E & R Machine.
In 1977, the city garage at 211 Grand Street, Lockport, NY, was purchased by Sterlin Arms from the City of Lockport. In April of 1978, both E & R and Sterling were moved from Gasport to the new facility in Lockport. In 1990, E&R was sold by the President, Eugene Sauls, to his son Gary Sauls.

His story ended her with the exception of phone numbers of Sterling and E&R family members he was able to track down. But if anyone knows better or owns a Sterling let me know!