I follow this forum, but generally have nothing to add, so keep my mouth shut! After reading so many posts where folks ask “is (xyz) corrosive?”, I became curious about how one might determine corrosive/non-corrosive just by shooting said ammo. When I bought my M1917 in about 1966, I bought a bagful of early to mid 50’s surplus ammo. After shooting that up, it was all store-bought until I began reloading. I have no recollection of how I cleaned my rifle back then, but I’m sure it involved Hoppes #9 & 3-in-1 Oil. The ‘17’s bore is still OK, so I guess I lucked out??