I picked up a nice used 30 round MP5 mag the other day. Its a true HK but it had a very interesting electro pencil engraved marking on it.
It has EGG/DOE engraving on the back. I know DOE usually stands for Department of Energy. But not sure what EGG stands for other then an breakfast item....
VP9 w/ match weight comp.
Probably the user's initials!!!
Like AGG said, probably initials. I know a lot of cops usually etch their ID numbers into their duty magazines.