.50 BMG manufacturer ID

I came across a US made .50 BMG case with the head stamp “KS 43”. Since I never seen such one before I wonder who made it and if it was one of those short term production runs by a plant that usually made other items.
Can anybody identify it?

From the IAA Headstamp Listing:

“Allegheny Ordnance Plant (operated by Kelly-Springfield Tire Co.), Cumberland, MD, USA”.

I hope that’s what you’re looking for.

Jon, thanks a lot!
Is there particular time period for this head stamp?

Could be wrong, but I would assume very limited WWII production, probably only 43-44.

  • @ EOD: “KS” => Allegheny Ordnance Plant, Cumberland [MD] which was operated by Kelly Springfield Tire Co. between November 1942 and September 1943. Liviu 08/20/07

Thanks a lot Liviu, so the code was only used for about ten months.