Checking my 1926 E.K. Tryon catalogue I find the Keystone single, for $11 with extractor and $12 with ejector. Looks very similar to the Iver Johnsons. No Keystone double that year though.

They also had guns called Vulcan which were very obviously Crescents both doubles and singles and even used the same model numbers as the Crescents in a 1926 H&D Folsom catalogue.