The rifle barrel at least of your drilling carries Nitro proof marks, so should be good for obtainable 9.3x72R ammunition. It's shot barrels will almost certainly be chambered for the 65mm (2 9/16") length shells. As noted modern day 2 3/4" shells are loaded to higher pressure than this gun was proofed for.


Miller/TN
I Didn't Say Everything I Said, Yogi Berra