Appears a rather random use of case colored 1950 into1954 with some blued steel scattered in. I can't identify a time when all non-brass, caliber or model, was used vs brass. I logged the info if reported but we didn't put an effort into determining when or at what ratio brass was used.
We were too busy collecting serials and LBC to worry about internal parts. Actually, we didn't know enough about the 50's rifle to know what to collect.
