[sheepherder]

Stick a #2 pencil eraser-first into the barrel...If only the eraser goes in, it's 7.65mm...If the whole pencil goes in, it's 9mm...

As to the chrome...Imagine if you will, that your pawn shop has one of Elvis' original guitars...(He had many)...but someone has sanded it down, and painted it in Barbie colors...with flowers...Would you say it is worth as much as one of The Kings unbastardized guitars???

Yes, you are correct about many servicemen having them chromed/nickled...and if it was your father/granddad/uncle who did it, then it has value to you...but not to anyone who collects Lugers...

There is a segment of the gun world who do seek out chromed or nickled guns...especially Lugers...If you were to sell it on GB, you might realize as much as an unchromed Luger...but you may have to wait quite a while...