I picked up a drilling that is a 16 gauge double barrel with a rifle barrel marked 9.3x72 Normal. The gun uses exposed hammers. In English the shotgun barrels are marked Nitro Proofed and Fluid Steel. The underside of rifle barrel has 3 numbered stampings, 118.35 which is the numerical conversion for 9.3x72, which I already know so that is no help, the 2nd stamp is 5.11, and the third is 584. What I'm trying to find out is if this rifle barrel is built for smokeless cartridges, or black powder cartridge. I find lots of info on the net about the 9.3x72R Normal, and I understand that it is the attempt at standardizing all the variations in the round. I also learned that the cartridge started as a black powder cartridge and of course later became smokeless, and can still be purchased as such today. But I can't find anything that directly correlates the "Normal" to also the switch to smokeless. So I don't know if I can shoot the modern ammunition in this or not. I'm having a gunsmith slug the barrel so that I can determine bullet diameter, results to come, so that will be another piece of the puzzle. Any help or guidance?

The "second stamp" 5.11 you mention is the proof date, May of 1911. The 584 is a proof log book entry number. Between the 1911 date, the nitro proof marks on the shotgun barrels, and the similar 'normalization' date of the 9,3x72R (pre-1912), my take on this drilling is that it was intended for smokeless powders. If there are Nitro proof marks on the shotgun barrels as you say, the rifle barrel should have (but may not have in 1911) a crown-over-N mark signifying nitro proof as well. Modern 9,3x72R ammo, assuming the drilling is in good solid condition, should work fine in this one. Don't be too surprised if the barrel only slugs .360" or so; all of the 9,3x72R barrels I have personally slugged have been between .360" and .363"

Added later: The CIP maximum pressure for the 9,3x72R is 2000 Bar (29008 psi) which is lower than the CIP maximum for 45-70 of 2200 Bar (SAAMI max 28000 psi = 1930 Bar); compare to the CIP max pressure of the 30-30 of 3200 Bar (SAAMI max a bit lower at 42000 psi = 2896 Bar). All this is to say that the current 9,3x72R ammo is still loaded to black powder pressures in a manner similar to current major commercial manufacturers' smokeless 45-70 ammo.

References: the German loading manual "Viederladen" 4th edition and the software package "QuickLoad". Viederladen also makes a point of the barrel diameters (bore and groove) of the 9,3x72R being smaller than more modern 9,3s.

Wow, this is all great info. Thank you. I don't have the crown over N mark, what is on my rifle barrel appears to be a crown over a G, and another that is a crown over a U. Any info you have on those markings would be appreciated. I haven't heard back from my gunsmith yet on the slug info. But he's been pretty good about moving things along for me.

Crown-over-G is the proof mark for a rifled barrel and crown-over-U is the "passed final inspection" mark. Marks on the shotgun barrels should include crown-over-S for smoothbore and perhaps a crown-over-W for "choked barrel".

Gunsmith got back to me. Slugs at 0.363". The Sellier and Bellot cartridge is a copper jacket 196 grain at 0.366". I'm guessing not a problem?

My Merkel 302 9.3X72R over 16b slugs the rifle barrel at 0.364" The S&B factory ammo is accurate in mine
Enjoy
Jim