doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com mystery caliber 9.3x??

Mike,

Thats my next question, bullet type, I assume "soft lead" bullets are more appropriate? Would "hardcast" be too hard to work with the rifling

Yes, Mike, I had my 366408 shortened back in the late 60s or early 70s. Turned out about 185 grains. Used it in several 9.3x72R drillings and a beautiful Sempert and Krieghoff kipplauf and even a 9.3x82R bolt and a 360 2 1/4 Purdey double. Unfortunately, all gone now. I still have a good supply of 200 grain Norma and 193 grain RWS jacketed for the 9.3x72R. I have never tried them in my 9.3x57 Mauser or my 9.3x74R although I did try some 250 grain 366408 bullets I had cast in the pre shortened mould in the 9.3x74R with good results. My current small 9.3s are 9.3x57R (360) Husqvarnas, a combo and a 33 single. For these I had two moulds made up by Tom at Accurate, the 170 and 200 I mentioned previously. The Huskies have a very slow twist. The 9.3x57R (360) rounds are loaded in my old 9.3x72R RCBS dies. Of course they seldom if ever need a full length resize but I only size down to just above the web anyway. I use 9.3x72R brass by Norma and DWM to make the 9.3x57R (360). My standard cast bullet alloy for 1200 -1500 fps is 1 to 20 but I might go to 1 to 16 in rifles where I might be seeing 1600-1700 fps. Commercial bullets that claim hard probably use antimony to get there and oddly that might give problems with leading in some rifles. The only bullets I cast hard are some linotype ones for the 22 Hornet which I may not have needed to but I was given the linotype and that was the only use I could think of for it. No lead will be too hard for your barrel but it may not give the best results. The factory jacketed bullets for the 9.3x72R were soft metal, copper or gilding metal, to be kind on the older barrels.

journeymen,
I use wheel weights and drop them in water from the mold. This makes a hard bullet and I try to size my bullets .002" over groove diameter, but I'm not overly strict about that. I use a .364" bullet in a 9.3x72R with .358" grooves. These came from a joint casting session with a friend, using my mold and his lead. They are not my usual WW and we sized the whole pile to .364" because his groove diameter was .362". I intended to resize my half to .360" but I tried some and they shot great without leading the barrel, so I didn't resize them. Note Halfadouble's advice above, you may want to go by his rather than my experience.

HalfaDouble
I will comment on your post tomorrow, my wife is calling me to supper.
Mike

HalfaDouble.
When dealing with old metric ammo it is always welcome to read of other people's experiences, thanks for yours. I had actually been looking for a decent 9.3x57R an found a BF advertised as such. When it arrived however the rifle barrel was 12.17x44R. I could have returned it but decided to play with it instead. I made cases from 8x50R Lebel and used .509" 50 cal. bullets with 5744. When other chances came up, I was a day late and they were sold before I saw them. I think your 33 was one of them, I was especially sorry to have missed it. I am hesitant to drastically shorten 9.3x72 R cases when I can use something else. I use original length (2.125-.130") 38-55 cases even though they are up to 1/8" short. When I make 6.5x58R S&S cases from them they stretch enough to be more like 1/16" short. I am making 8.25x57R/360 Hagen brass now from them for a new project. I just seat the bullets "out" to the normal oal. The only complications are usually the requirement to alter the rims and may need to size the necks in another operation to be able to hold the bullets. I brought back from Germany a supply of RWS 9.3x72R cases and bullets and stumbled into an opportunity to add to the bullet supply with a quantity of S&B 193gr .366" bullets whereas the RWS were .364". Both of these bullets can be used in rifles with groove diameter all the way down to .352". For the more powerful 9.3s I use bullets from a supply of old Speer 250 gr. and both RWS and Norma 286gr. The 250 gr Speer stabilize in the 9.3X72R S&S which wouldn't work with bullets as long as the 258 gr. H Mantel or 293gr TUG. The S&S is an entirely different cartridge than the 9.3x72R N (.473" vs .427" base dia.).
Mike.

I have some cerosafe on order. I was able to scope the bore and the chamber seems a little rough, bore looks superb luckily

I too think this is your chambering. I have chased down several of these in the last couple of months. You can look up some of my posts in the German section above for detailed discussions. A couple of general comments.

- The 9.3/57R - .360 is 15 mm longer than the 9.3x72. This is much longer than accounte for by the 15mm.
- Many of the break action stalking rifles are found in this caliber.
- There are at least three distinct versions of the 9.3x72R, even without drifting off into the Sauer and 82mm versions. It is not uncommon at all to have a chambe that won't seat a modern 9.3x72R Norma case. I bought one drilling on a GB auction. The austion house said that they presumed it was a 9.3x57R since the 9.3 x 72R ammo lacked 1/4" chambering (very similar to yours). I contacted them and asked them to use a new unfired case or a resized clean case. THey did and the 9.3x72 fit perfectly. The old guns are very sensitive to oversized or dirty cases, even to a small degree.
- I bought another drilling, marked exactly like a 9.3x72, but the ammo wouldn't fit, not even empty cases. I neck sized the cases in a 35 Whelen die, and they fit. A lead slug of the bore showed it to be a true .357 barrel.

As a general rule, in an older gun, my first guess would be that it is a tight chamber in the longer version, or it is not actually a .366 bullet. For years, all the ammo loaded used a reduced diameter bullet with a short driving band. These are not readily available any more and you really need to use bullets of the proper diameter, with the neck sized to the proper size.

If it is a stalking rifle, my first guess would be that it is a 57mm case.

Keep in mind too that just because it is modern ammo, it isn't necessarily exact. I recently bought a high grade O/U combo gun with an 8x57R rifle chamber. It was made in Berlin in 1938. New factory 8x57R ammo wouldn't chamber. I tried new 7x57R. Same story. A barrel slug showed a .323 groove diameter. I found that old German military 8x57 form the WW II era went right in (but of course didn't extract). My guess was correct that the old ammo had the correct .469 base diameter. All the new ammo (S&B) was made to the "30-06 standard" of .473. This was true even though it was European ammo. The rifle was made to such close tolerances that it wouldn't chamber the world's # 1 standard case head. To solve it for the future, I took a 308 reamer and just barely relieved the breech end of the chamber to a proper size, and used a small fine stone in a Dremel to relieve the hardened extractor the same few thousanths. It is undetectable except under a magnifier and you can make ammo from any appropriate donor case.

AGS The 8x57 and 7x57 were not made on the same head size cases, nor were the rimmed versions. The 8x57/I/IS/IR/and IRS were made on the M88 case head diameter of .468", whereas the 7x57/ R were made on the M93 case head diameter of .473"(The 30-06 is said to have been copied from the 7x57). It is possible that S&B made those 8x57R cases with the same draw dies as the 7x57R (M93). Modern manufactures often make ammo with case heads different diameter than original design. My brother had a 6.5x55 caliber rifle and was handloading with modern American cases (with correct headstamp), with .468" head diameter. Actual measurement of 30-06 and other 06 size cases often show head diameter of .468". This is all OK as long as they use the smaller size but can cause confusion if they use a larger size. We often talk about "tight chambers", and they do happen, but the problem can also be the ammunition rather than the chamber.
Mike

Journeymen, how is the Cerrosafe cast coming?

You are correct and the point I was making was that some of the 8x57 R is made with the .473 head. I checked some S&B 7x57R and it is .473, so again it wouldn't work to fireform. THis was a case where precision caused a problem. A little slop would have come in handy.

AGS,
Yes, sometimes a little slop does come in handy. I was fortunate enough a couple times to buy once fired cases from a firearm manufacturer and had way more 7x57R cases than 8x57R cases and made up some 8x57R cases using the 7mm ones. They were close enough that "polishing" rather than "turning" the head diameter (after sizing as much as possible) allowed their use. A lathe, where I worked made things easier, without access to a lathe, a drill press would also work. BTW, this exercise is what taught me the difference between the cases.
Mike