U.S. GI .30 Spam Can Finishes and time periods

I recently had a discussion with a gentleman about US GI Spam Can finishes relating to the time periods for the .30 M2 Ball. I have a 240 round can made by RA and the lot is 43030 and the finish of the can is just galvanized steel and I assumed that it was mid '50s production. The only things that I have for lot #'s is the TM 9-1305-200 dtd June 1961 and on page 27, shows when the last corrosive primed ammo was accepted, (which has also been posted here many times), and a box of RA M2 Ball, lot #43297 having the head stamp RA 57. The information that the gentleman had was that spam cans with just the galvanized finish were WWII time frame and later cans, such as '50s on up, have an OD finish. His information also suggested that the lot # blocks could be issued non-sequentially or that they could be repeated. He is also a big collector of spam cans. Is there any documentation out there that would tell when spam cans switched from GF to OD? Thanks, Bruce.

My observation is that OD finish spam cans were used from first introduction in 1944-45 time frame until early 1950s especially on ammo delivered from the maker in spam cans.

The bare metal (tinned or terne plate?) spam cans seem to have been early 1950s repacking of earlier WW2 ammo presumably delivered in the wood M1917 crates. ALL the ones I have seen came from Hawthorne, NV, but I am not sure if they were operating under Navy or Army control at that time. I think Navy.

This does not rule out original delivery from the maker in bare metal cans, just I have not seen any.

Lot numbers were NOT recycled after being used. However, ammunition repacked in a different container would keep the same ammunition lot number. However, if the ammo was repacked in a different configuration (linked or in clips) that could result in a new lot number.

Lot numbers were used for quality control purposes and as ammo degraded over time, bad lots would be identified by number and declared to be unserviceable, limited to training use only, or requiring certain action (inspect for loose bullets or something). This information on ammunition status would be sent out (monthly or quarterly?) and activities were supposed to check their inventory records to see if they had any of the bad lots and take appropriate action.

I agree with John. I am not an expert, but have seen hundred over the years and also opened dozens to take note as to what is inside before burning it up in MG’s. My observation also is that OD finish spam cans were in use from the early 1940’s into the late 1960’s for USGI carbine ammo especially. The bare metal, or as John calls it, “tinned or terne plate?”, Spam cans, seem to have been 1950 onwards repacking of earlier WW2 ammo and also 1950’s headstamps and lot numbers. All the ones I have seen and opened came from Hawthorne and Pueblo. Like John states, “this does not rule out original delivery from the maker in bare metal cans, just I have not seen any.” Me either. Lot numbers recycled, I serousy doubt that.