It would probably be HD Folsom They were in business for a long time and sold all kinds of guns.
http://www.gunbroker.com/Auction/Vie...Item=142944188
An interesting headline from the nyt 1900
SHOT BY HIS EMPLOYER; Head of H. & D. Folsom Arms Company Under Arrest. Says Second-Hand Revolver Was Accidentally Discharged --- Peter Koller, Wounded Man Now in Hospital.
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E-MAIL
July 3, 1900, Wednesday
Page 5, 1057 words
While examining a pile of old revolvers lying on a counter in the store of the H. D. Folsom Arms Company, at 314 Broadway, yesterday noon. Henry T. Folsom, the head of the firm, accidentally, shot and fatally injured Peter Koller, one of the salesmen. Koller, unconscious and in a dying condition, was taken to the Hudson Street Hospital.