Hi 2-piper. I agree with you on bore dia., but if barrel is marked 9.3 which equals .366 and Factory 9.3x72R ammo with .366 bullet fits chamber someone might think it's OK to shoot and should be accurate.
As Der Ami stated "these rifles is a "law of it's own". If you could go to the "Mall Mart" and buy ammo, it wouldn't be nearly as much fun." When someone see you out in the woods with a drilling, they just got to stop and ask.
For anyone just reading this post, Unless the gun is shooting when you receive it, you need to check bore/groove dia.
I purchased this gun in early 1980's. Only my second drilling, first one was 9.3x72R purchased only one day before. Seller had no clue on rifle cal. I know I didn't cast chamber/bore back then. Don't remember how I did it, but probably used .375 dia. soft lead ball to get bore/groove dia. (I have that mold) along with hardwood dowels to verify 72 rimmed case. Then purchased lead molds. Finally tried .348 200gr. Hornady. They are accurate, but don't open to good on deer at lower vel. (just punch a hole thru). I didn't have "cerrosafe" back then. Got it grouping OK and didn't look back. This year I used T/C contender pistol in 357 Max to harvest 8 pt at 75 yards, Like to rotate and use diff. guns. Don't think I bought a factory loaded rifle shell(to shoot)in my life.
[pilgram, I'm new to this forum, but I already know these guys can get you up and shooting. Rolling your own if need be. You just need to ask them.

wknitro