I'm far from an expert, but if you really want to learn about your M1 go here.
http://forums.thecmp.org/forumdisplay.php?f=7From what I see you have a somewhat typical mixmaster M1.... WWII Springfield receiver (September 1941), stock, op rod, bolt and hammer in a Winchester trigger housing. Not sure of the barrel but maybe a post-war (1957) Danish rebarrel?
*Man, ya gotta be fast here, ya got several good replies before I could type it out! Nice rifle, shoot and enjoy it.