WW1 Erfurt stamped S/42?
 

So as you can see my WW1 Erfurt is stamped S/42 on the barrel. There are no WW2 markings anywhere else on the handgun. The witness mark seems legitimate and the SN matches. Any ideas gentlemen?

I understand from previous forum discussions that some armorers replacement parts were marked with S/42. Perhaps that is what this is.

Neil

That is exactly what it is... your Luger had it's barrel replaced with a barrel produced by Mauser.

Thanks everybody. So was it common during wartime to add the guns serial number to the replacement barrel?