Frank,
I was able to slug the bore. The grove dia measured 0.314";the bore 0.306"+, but that was a bit difficult to get a good reading. This would suggest a grove depth of 0.004" which seems reasonable.
The bottom of the barrel is marked 7.6 mm which would calculate out to 0.2992" or really 0.30". I read that the 7.6 mm is supposed to be the bore diameter prior to rifling. Either the rifling process must open the bore a bit or the Germans were sloppy with their "thou's" ????
Anyways, I'm awaiting the delivery of some reloading components that were a part of the sale; brass, bullets, dies, and a mold.
Fun to mess with something different!
More to come.
Mike.
frnkeore wrote on Dec 18
th, 2017 at 1:58pm:
Like Joe says, you need to get the rifle in your hands, before you can do anything.
The bore is usually marked under the forearm (usually 7.7 or .303) but, the groove has to be measured, it can run anywhere from about .314 to .321.
The chamber necks and throats are very long and tapered so, you need to know what you have to make your cartridges.
Please come back to us when you know more about it. A chamber cast helps but, it can be done w/o one.
Frank