9.3x72R with Early German "D" Chamber

[mike ford]

cwbuff,
I'm confused. Are you sure the "norma 9.3x74R case you have is not a 9.3x72R case made from 9.3x74R w/o the headstamp being removed? The headsize of both 9.3x74R and 9.3x72R S&S are enough larger than 9.3x72R,that it should "fall in". If you have a 9,3x72R D, and want to use factory ammo, you will have to rechamber it. If you handload,you can use normal dies, without buying a special set. If you size the normal case enough to fit into the chamber(also considering the rim), and fireform it, then the normal dies will work. A 38-55 file trim die,357Herret forming die, or similar should get the case small enough to fit the chamber. Just size a little and try it, until you can chamber it. In my experience, barrels marked 118.35, like yours usually have a .357-.359" groove diameter, which makes bullets pretty easy.
Mike

[cwbuff]

Mike - I think I am the one who is confused. It has been a long time that I took the Drilling out of the safe to look at it. I have been trying for some time to figure out what cartridge the rifle is chambered for. I did the Cerrocast chamber cast, took some measurements and guessed at the closest cartridges based on the specs. I ordered two different cases from Buffalo Arms. One was the 9.3x72R (modern). It hangs up with about 1/2" protruding from the chamber. The second one was an 8x72R. It drops right in but will the breech will not close due to the thickness of the rim and the bore is clearly larger that 8mm. Above I stated that this was a 9.3x74R case. That is the head stamp on the case, but the bag the case came in is marked 8x72R.

[cwbuff]

Based on the proof marks on the gun, I have this Drilling dated between 1891 and 1911. The earlier date (1891) is based on many of the proofs being in use from 1891 to 1939. The later date (1911) is based on the markings "2 g Sch. PNA / 27 G Bl" which I read was a pre-1912 voluntary smokeless powder proof. From what I can tell, these early German proofs are still the subject of a lot of research. I found and NRA site that did not list the earlier proofs stating that they were still a subject of investigation. I would love to find a serial number database on Fredrick Wilhelm Heym (Suhl) guns to date this specimen.

[sharps4590]

Mike, cw, I wondered about what was posted also. So much so that after Axel posted about the Sauer cartridge I checked the dimensions on the X74R, X72R and the Sauer case. The X74R might fit if it is the Sauer 9.3 X 72R. Head size on both is close. I checked them this morning and have forgotten already. I'm wondering if the 9.3 X 72R case mouth is hitting the shoulder of the chamber thus not chambering?

[Axel E]

Friedrich Wilhelm Heym opened his firm at Mauerstrasse 3, Suhl, in 1865. F.W. was the owner until 1920, so F.H. may be his own mark. But there were idependent gumsmithes, outworkers with these initials too, f.i. an actioner Franz Heym, mentined 1913.
L.K. is an early mark of the Suhl barrelmaker Louis Kelber, Trübenbachstr.1, founded 1894,existed to 1945.
The proof marks on the shot tubes are crown/S = shotgun, crown/W = choke bore
The service load info the shot barrels were proofed for was 2 gramm Schulze Pulver Neuer Art / 27 gramm Bleischrot = 31 gr Schultze powder new kind (= improved), an early smokeless / .95 ounce lead shot. The German name of the nitrified wood powder inventor was Schulze, but the British spelled "Schultze" to clarify the pronunciation.

[Axel E]

Your 8x72R cases reworked from 9.3x74r brass may not be perfect, maybe made for a Maximum chamber and still too big at the base for your chamber. Take a modern 9.3x72R Normal case and smoke it full length with a candle flame. Chambering it will show where it hangs up. While the modern 9.3x72R, as normalized in 1910, features a straight taper for almost the entire length, the 9.3x72R D had a quick taper near the base and then was almost cylindrical to the mouth. So a 9.3x72R Normal willhang up in a D chamber at the point where the straight taper gets thicker than the cylidrical part of the D chamber.
BTW, in 1898 old Wilhelm Brenneke (not Sauer & Sohn!) based his 8x72R on the D case. While the Nimrod and Normal cases had a max base diameter of 10.91 mm = .4295", the D was 10.95 – 11.0 mm = .431 - .433". Not a big difference, but enough to stop a max case from entering a min. chamber completely.

[cwbuff]

Thanks - I will try that.

[mike ford]

cwbuff,
As I suspected, and Axel verified,the case you got from Buffalo Arms was reformed from 9.3x74R cases, by swaging(resizing) the about .465"head diameter head diameter to about .427". This is a valuable service Buffalo Arms provides for owners of obsolete caliber guns, but it often creates confusion because of the head stamp. This also causes a couple possible reasons for the failure to close.The least likely(since your case is 8mm)is that in the process of reducing the diameter, the brass has to go somewhere.The case, therefore,will lengthen significantly.Even forming 8x72R from normal 9.3x72R will require trimming to length, and starting with 9.3x74R will require even more.Rim thickness and/or diameter is the most likely cause in your case. Remove the barrels and push the extractor into the closed position. Place the reformed 8x72R case upside down in/on the rim recess.If it fits in, but stands proud(high), it is too thick. If it won't go in, it is also too large in diameter.Also, the rim recess is likely cut with a radius in the corner.In reducing the rim diameter, not accounting for this radius by putting one on the underside can cause failure to close.I noticed your drilling is a hammer gun.The firing pin for the rifle in this type drilling is set at such an angle that rifle primers often cause misfires, and it may be necessary to use pistol primers. Since pistol primers are not as thick as rifle primers, you may find it more convienent to thin the rim from the rear.This also has the advantage of removing the confusing headstamp. BTW, using 8x72R cases to fireform to 9.3x72R D is a pretty good way to go,since you won't have to find a 38-55 file trim die. Try this and let us know what you find out.
Mike

[cwbuff]

I marked the 9.3x72R case with a sharpie and inserted in the chamber. When it hung up (about 1/2" sticking out), I spun it around in the chamber. You can see from the picture that the case hangs up about half way down the case. Next to brass case is the chamber casting. I put the calipers on brass case where it hangs up. It measures 0.3975" The Cerrosafe casting measures 0.3945 (after compensating 0.0025" for the Cerrosafe expansion). So at that point, the chamber is 0.003" too small. So one option is to send the casting out and have a custom die set made. Does anyone have any experience with custom die sets?
DSC_0002.jpg

[mike ford]

cwbuff,
It's your money and you can do what ever you want with it.Of course an expensive set of custom dies would work like it was made for it(it would be). If you feel like you have to go that way, I suggest "CH 4D". You will still need to account for the rims.
Mike

[Axel E]

I marked the 9.3x72R case with a sharpie and inserted in the chamber. When it hung up (about 1/2" sticking out), I spun it around in the chamber. You can see from the picture that the case hangs up about half way down the case. Next to brass case is the chamber casting. I put the calipers on brass case where it hangs up. It measures 0.3975" The Cerrosafe casting measures 0.3945 (after compensating 0.0025" for the Cerrosafe expansion).

Exactly what I suspected! I know a man who solved this problem in a more rustic way: He first resized his 9.3x72R brass using, of all things, the sizing die body (without any innards, of course!) of his old .38 Special RCBS die set down to about 20 mm from the base, until they chambered in his rifle. Then he expanded the necks and loaded them. The cases looked quite silly now, almost an hourglass shape, but after fireforming they were okay for the rest of their life. He used "standard" 9.3x72R Normal reloading tools thereafter. Never needed to resize the offending area of the case again, he told me.

[cwbuff]

That is a very interesting solution in that it allows the use of commodity dies without modifying the original chamber on the drilling. I did something similar when I needed to load 9mm Browning Long ammo for a FN 1903 Browning. I found some fired cases, but no die set. So using trial and error, I found a combination of 38 Auto and 9mm Luger dies that allowed me to reload the cases and shoot the pistol.

[mike ford]

cwbuff,
Axel's friend's solution is the same as I suggested, using 38-55 or 357 Herret (35 Rem may also work,there are many ways to skin a cat) dies.I believe live ammo could be sized to fit with 38-55 dies,except for the rim thickness.The 38-55 dies are also standard and wouldn't work the brass too much.You could even borrow the dies in the begining, because after fireforming you wouldn't need them again.Of course,if you don't have your brass yet, you can fireform 8x72R brass, after accounting for the rim thickness.It is not necessary to use a bullet to fireform the cases if you use a 1/4 sheet of tp over the powder and fill the case with grits,corn meal, cream of wheat, or similar;then stop it up with more tp or similar.
Mike

[cwbuff]

I have a 38 special (357 Mag) on my wish list anyway. So I will give that a try.

[Axel E]

Your 9mm or .38 Auto die may even be better suited instead of a .357 one, as these are wider at the base. Provided the fl size die body is bored straight through.