IBM m1 carbine

[MarkV]

A receiver like that would have NEVER left the factory - IMHO is has nothing to do with the original manufacturing. It appears to me that someone took a very rusted receiver, removed as much as possible through sanding or chemical wash and then re-blued it.

[guns ltd]

I have seen this before on a lot of carbines that were not cleaned properly from use and then repacked for storage. It is pitting. All orginal carbines were parkerized. gray or black. Cosmoline makes them turn green. If this rifle was repacked dirty fron field use the cosmoline would lock in moisture and that is the result. While seeing hundreds of carbines coming in from all over the world during the 80's a lot of these were redone.( Reparked) with the same effect. Importers were Blue sky, Arlington Ordance, etc. Keep a light coat of oil on it and it will be fine. DON"T USE WD40 please. This stuff leaves a film that dried out.
Hope this helps.
John

[madpsu]

Thank you all for the help. I should have run from this one . Live and learn.