Originally Posted by mustangsnmules
The markings on the barrel state that this is a 8.8mm which is .358 dia. a 9.3mm is 366 dia.
Slug the barrel and cast the chamber and throat.
I spent several years trying to figure out what caliber my drilling was. I ordered a set of 9.3x72 dies with a 35 cal. expander from Lyman and was able to work up loads. The 8.8x72 and 9.3x72 are both old black powder cartridges.
You are correct, a chamber cast will need to be done to verify 100% what the rifle chamber is.
But According to the markings on Danno's rifle, it is chambered for 9.3x72d (the 9,3-72d tells this)...unless it has been rechambered.
9.3mm being the groove diameter and the other 8.8mm stamp by the proofing mark denotes the bore (land) diameter.
Here's where it gets interesting...
There are at least 4 different 9.3x72 cartridges.
-A 9.3x72d would be the old 9.3x72 Deutsche. This is a completely different cartridge than the common 9.3x72R as seen today. It has a short taper from the case head about 30mm forward, after that it is essentially straight walled. Very easy to ID this one visually.
-The 9.3x72E is the English (British) version and has a straight taper from head to mouth. This one looks like the current 9.3x72R Normalized except it is slightly smaller at the case head and rim.
-The 9.3x72R Sauer is a completely different critter. It's a bottleneck cartridge with a small shoulder. It looks a lot like the modern 9.3x74R, which is a lengthened version of the 9.3x72R Sauer, but it's an old low-pressure cartridge.
-The 9.3x72R as commonly found today is what is called the Normalized version. It's a compromise cartridge from right around 1905...the design made slightly larger so that all of the older 9.3x72 chambers (except for the Sauer version) could be reamed to this new standard chamber. A normalized cartridge won't fit in the older chambers by design, but with the proper dies and sometimes a little rim modification, modern normalized brass can be used to make the older d and e versions.