The F stands for Folsom. In 1919, H & D Folsom Arms Co., 314 Broadway, NYC, acquired the gun making portion of the Baker Gun & Forging Company of Batavia, NY. From then until about 1930 Baker and Batavia guns were made at the gun factory H & D Folsom Arms Co. owned controlling interest in in Norwich, Conn., where they also made their American Gun Co., Crescent Fire Arms Co., and hundreds of "trade brand" guns.