Unusual Springfield M1A engraving

[Kyohte]

Under the receiver is engraved "A101" by hand. I tried googling this but found no useful results. The rifle was put together in early 1994 and has all USGI parts minus the receiver. Is the engraving of significance or something put on by the original owner?

[Different]

That marking is typical for the period. The "A101" is a casting pour lot code. Gray-Syracuse Company (Chittenango, NY) made the raw castings for the M1A receiver from about 1973 until the end of 1996. Valley Ordnance (Wilkes-Barre Co.) machined the M1A receiver castings for Springfield Armory, Inc. from 1971 until July 1996.

The raw castings and certification papers for each production lot were shipped from Gray-Syracuse to Valley Ordnance until closing in July 1996. Valley Ordnance machined the castings and then shipped the receivers to Springfield Armory, Inc. for heat treating, phosphating and assembly into rifles. Between M1A receiver serial numbers 0320XX and 033964, the pour lot code was first marked on the raw casting. Gray-Syracuse was the casting supplier for M1A serial number 100042 but the vendor had changed to another company by serial number 101255.