Are you real sure about the "Strosnider" spelling? I checked both American Gunsmiths, by Frank Sellers, and Gun Trade In America, by Jerry Noble & Tom Moore, and neither one lists anyone with that name. These two books contain 99% of all known makers and related tradesmen. I have also encountered rifles with a name on the underside of the barrel, or even on the top flat, away from the original maker's stamp, that I'm very sure were put there by someone who re-cut/re-rifled the bore.