First of all it appears I deleted the pictures I had so I will have to take some more. A couple weeks ago I received a very nice old hammer drilling. Case colors still very much in evidence, Jones underlever tight as a tick on a dog and the bores appear as new. The only...issue....with the drilling is the chambering. It is marked the typical 118/35 for the 9.3 and on the right side of the rifle barrel is stamped, "360-57D" which led several GGCA friends and me to assume it was the old 360 Express as it's known in Britain and 9.3 X 57D as it's known in Germany. Tain't that cartridge!!

A chamber cast revealed something entirely different and neither my GGCA friends nor I know what it is. It also revealed that the bore is actually 9mm and not the 9.3 we assumed. This is just another example of why one should ALWAYS cast the chamber and slug the bore of an old firearm. After pouring over several of my books I determined the case could be made from 30-40 Krag cases or, in a pinch, 303 Brit. Both will be short but the Krag case less so, only about .002. Thanks to the kindness and generosity of Idaho Sharpshooter and npd, and 218 Bee's equally generous offer, I have a supply of Krag cases. After the cases arrived I formed them to 9mm and loaded the fireforming load which consisted of 14 grs. of Trail Boss under a 250 gr. cast, gas checked bullet of 50/50, lead/lino. It shoots and shoots very well even with the forming loads!!! However, it is also about a foot high at 100 yards so a new, taller front sight is in the near future.

The problem with the drilling is that it isn't Nitro proofed. According to the Proof Marks it was made between 1893 and 1912. That transitional period between black and smokeless. One of the reasons I bought it is that the 360/57D was a black powder case, a propellent I dearly love to work with. That it has been rechambered, and probably on these shores, seems to be beyond doubt. Now I have to work with a modern, bottlenecked case designed for smokeless powder in a rifle barrel that is not Nitro proofed. I have considerable experience with "Nitro for Black" loads and figured that was the path I would take. Then I remembered the bottle of Trail Boss I had. I have used it for reduced cast loads in big bore "loudenboomers" with good success so decided to try it here. So far so good. Groups size was impressive for my 61 year old eyes firing across open sights.

If the wind lays today I will break out my chrono and see where the velocities fall with the Trail Boss loads. I also tried a 15 gr. load of Unique with an open cell foam filler and it shot well. I will chrono both.

Right now I must needs prepare for church!

keep us posted!
I love projects like this!
shane

Still didn't get any pictures but the wind at least slowed down enough I set up the chrono. The Trail Boss load had seemed quite mild and when I ran it across the screens the reason became evident. Average velocity ran 1275 fps. with 903 fpe and the rest of the numbers were nothing to write home about. I then tried the 15 grs. of Unique load utilizing an open cell foam filler. This is more to my liking. Average velocity ran 1480 fps with an energy number of 1216 fpe. The rest of the numbers on this load were very good. ES was 8, AD was 2.8 and SD was 3.5. The accuracy of the Unique load also bested the Trail Boss by 50%. Pressure with both loads left no indication of excessive pressure. Cases fell from the chamber when the barrels were elevated and fired case measurements did not change. Well..the neck and shoulder did but they're supposed to. I have no loading dies for this cartridge so am merely neck sizing the cses with another 9 mm sizing die and that die just touches the shoulder and squeezes it down about .003. I'm careful not to set the neck back.

As both loads shot very close to the same POI I believe I will make or have made or maybe try to buy a taller front sight, file it in and use the Trail Boss load for fun and plinking and the Unique load for hunting. Now to work with the shotgun barrels. My initial load of Federal hulls cut back for the 2 1/2 in. chambers, 2 1/2 drams of black powder and a once ounce charge of #6 shot was not very impressive.....or satisfactory.

I think yours caliber would be 9x57R/360 which mother case is 9,3x72R.

I believe that's what it was originally as it is so marked but it has definitely been rechambered. The various and old 9.3's based on the X72 case are all either straight or straight taper. This case is bottlenecked. In addition, the head dimension of those cases runs around .427 - .430 and this chamber cast, and subsequently fired cases, measures .460. Obviously no one alive knows what actually was done other than it has had the chamber recut The Krag cases have worked great.

How about then 9x57R ? Check dimenions from here:

http://www.cip-bobp.org/homolo...biical-en-page48.pdf

Nor is it a 9 X 57R. That was the first thing I checked after I cast the chamber. I have another drilling in 9 X 57R and a Sauer & Sohn Mauser in 9 X 57. In head and rim size it's close but no cigar. The overall case length is .2 longer and the shoulder is the same distance farther forward than the 9 X 57R. The greatest probability is that it was chambered here in the US as it lacks the Crown over R stamp for a repair or rechamber that it would have received had the work been done in Germany. I don't know if the 8 X 60 was ever chambered in 9mm, I doubt it as there was no need to lengthen a 9mm rifle cartridge as per post WWI law, but one can only assume that a possibility, if very unlikely.

This very rare but possible one:

http://www.municion.org/9_3x62/9_3x62R.htm

I wish I could interpret the numbers, the shape is similar.

Igor, in the bottom link, are those knives you make? If so, I really like some of them, nice.

quote:

Igor, in the bottom link, are those knives you make? If so, I really like some of them, nice.

Yes, I make them occasionally, I´m a pro artisan.

By the way, this software is very usefull when converting different measures:

http://joshmadison.com/convert-for-windows/

Welp...I converted the dimensions, forgot I had a conversion chart bookmarked, and that isn't it either but it's pretty darn close. Most important to me is the caliber is .366 and the .018 head difference. That's quite a bit. I'll just list my dimensions:

Case length: 2.32 from chamber cast
head: .452 from fired case
Rim: .542 30-40 Krag
base to shoulder 1.935 from fired case
Neck diameter .390 from fired case
shoulder diameter .428 from fired case
groove dimension .356 from barrel slug and casting

It has some dimensions in common with several different cases but not enough of any one case to call it something.

Load development continues. Just for grins and giggles I tried a BP duplex load of 4 grs. of SR-4759 and 56 grs. of Ffg, Scheutzen beneath the 250 gr., cast, gas checked bullet. Accuracy was not much to write home about and velocity didn't seem much different from the Trail Boss load....but I'm guessing at that as I didn't set up the chrono. I received some pressure data of the 9.3 X 72R and the loads used to produce that data and have a few more loads to try. Case capacity is quite close to the 9.3 X 72R and bullet weight is the same as I'm going to try. Also an RCBS two cavity mold is on the way for a 200 gr., gas check bullet.

As this crazy thing remains unidentified I've decided to call it a "30US X 9mm Improved"...lol!