At some point in time, Savage Arms Corp. instituted a policy that any Philadelphia built Ansley H. Fox shotgun that came in for repair would first be rechambered for 2 3/4 inch shells and proof tested at the owner’s risk, before any other repairs would be performed. If the gun failed proof, they offered to fit a new set of barrels at 10% below list as a matter of good will, before doing any other repairs. If the original Philadelphia barrels did pass their proof, they got this stamp --
same as they began putting on new Ansley H. Fox guns about 1938.
Between this policy and just the number of Philadelphia guns that Savage added a second set of barrels to, there are a lot of Philadelphia era Ansley H. Fox doubles out there with later Utica, NY, or Chicopee Falls, Mass. barrel addresses, and even a few with a Westfield, Mass. barrel address.