The round in question is for the German 7.92x57 military rifle. It appears to be a steel case with tin plated steel bullet. The case appears to be coated with an olive drab laquer or varnish. All parts react slightly to a magnet. The head stamp is as follows: At 12 o'clock is the number 51, at 3 o'clock is a symbol similar to the male icon, i.e circle with an arrow, at 4 is the minus sign, -, at 8 is a plus sign, +, and at 9 is the numeral 3. The primer is staked at two places. Questions: Origin, is it corrosive, is it detrimental to the bore or other parts and is there any other data availble?
