Does anyone know, where I might find shell casing Identification tables? I was looking over some federal .223 55gr. and on the end of the shell it has .223 Rem with two other stamped numbers or letters. I also looked at some Speer .223 and it just has 4 letter and number stamps. I know there has to be a table or book where I can decipher these stamped codes, but I am not all that proficent at the PC World yet. If there is a book or something online, I would much appreciate any information as to where I can identify any shell casing I might run into. All answers will be taken and very much appreciated. Thanks again.