A nice '03A3, probably a DCM gun back when. Some folks think such guns were rebuilt and cite the cartouche as proof. Not so. By the time the later '03A3's got out there, there were plenty of M1's to go around and many of the bolt guns went from factory direct to depot storage. They were later given to allied countries as military assistance and thousands were sold through DCM for $14.50, plus shipping. They were all proof tested before being released for sale, per army regulations, explaining the San Antonio Arsenal cartouche.
The serial number is far too high to be 1942 and a gun made in 1942 wouldn't have a 1943 barrel. That gun dates to early 1944.
Jim