I have a Springfield 06 that my Dad received from the NRA in to late 40s or early 50s. We customized and used it off and on. The serial # is 30912XX and is marked Remington U.S. Mdl. 1903, on the bolt handle it is stamped NS.I had always assumed that was for Nickle Steel. I believe it was made in 1941. Could anyone confirm that the NS. stands for Nickle steel ? we've run some hot load through it and never had any problems. Thanks, Geo.