This one from Marine Gene Gustad--Gene received the following info from History and Museums, HQMC...
Okay you boots:
(1) effective 1 July 1905, each enlisted amn's file cas was
assigned a number and the file case filed numerically. The first, or lowest number assigned was 20,000. The numbers from Zero thru 19,999 were reserved for Hq. "general file" correspondence.
(2) Previous to 1 July 1905, the enlisted man's cases were filed alphabetically and when there were two or more cases with the same nee, the cases were filed by date of enlistment.
(3)Circular ltr. 432 of 15 Feb. 1941 directed that beginning on 1 March 1941 the file cases became the identification , or serial number number for each enlisted man in the Marine Corps or Marine Corps Reserve. Enlisted men in the service on 28 February 1941 were assigned a file case (serial) number.
(4)Identification numbers were first designated as serial numbers. On 3 May 1950 Marine Corps Memorandum 45-50 was published directing the term "service number" will be used instead of the term "serial number"
(5)On 1 January 1972, the social security number replaced the
service(serial) number as the primary means of indentifying
(6)23 Jan 1944 1st 7 digit service numbe was issued.
(7)the last serial number was 2,787,444 issued to Miumea F.SAlevao, Agana, Guam.(6 Dec.1971)
(8)1 Jan. 1972 no more serial nos.
My serial no. is 392xxx.
Hope this answers some of your questions. SF Gene
I got one of the old MSNs when I joined in 1959. Mine was in the series 1697xxx. When I hit boot camp after my 180 day delayed entry program (allowed me to finish high school, lots of my fellow recruits had numbers in the 1800xxx or 2000xxx. Our drill instructors told us that the numbers 1700000 through 179999 were reserved for Women Marines.
I served 8 years, got out, and raised a family. When I re-enlisted in the Reserve in 1983 my SS# became my service number. I served in the Reserve (activated in Desert Storm) until my 60th birthday when I had to retire. My unit was activated shortly after my retirement papers went in. Boy was I sad that I couldn't go too.
Gary Coates,MSgt. USMC Retired.