Try this again

[Bama13]

I bought a Springfield 1903 modified to 35 whelen. The barrel has a stamp of a horse head with a F inside it. I was hoping someone might have information on the barrel maker or anything else.

 

[Rum River]

I did a google search on 'horse head barrel proof' and based on those results googled 'federal firearms horsehead'.
Check it out, sounds like they were a quality barrel outfit that was bought up by ER Shaw in the late 60's.