doublegunshop.com - home Forums Thread Like Summary - mystery caliber 9.3x??

I cant for the life of me figure out if this stalking rifle is 9.3x72r or if its a variant of that cartridge. I read a good number of threads on the 9.3x72r changes but the case dimensions dont seem to have changed enough to prevent older guns from chambering modern 9.3x72r ammunition

proof mark


wax cast and case



*this is a factory new case, not loaded ammunition or fired brass
*I know the caliper says .320, I re-measured it in a more stable position. The measurement came to be .312. This obviously doesnt include rim thickness


Slugged the bore with a .40cal soft lead musket ball. Groove is .365-.366"

Looks like i need to cerosafe it. I'd really like to use this rifle for opening day. Has anyone had success ordering 9.3x72r reamers?

journeymen,
The 118.35 mark on your rifle is the bore (not groove or bullet) diameter, expressed in gauge measurement. In my experience, this most often found on rifles with .358-.359" groove diameter. Also it is found on several different old 9.3 nominal cartridges and often the 9x58R S&S. This mark was used before 1912 and at this time there were different case forms. In terms of the number of rifles made, yours is likely chambered for one of the 9.3x72R cartridges. For this reason, I recommend you make or have made a Cerrosafe chamber cast. The wax chamber cast will show general case form, but not precise measurements. At the time this rifle was made, there were "D"(Deutsche), "E"(English), 360, and "N"(Normalizert or standardized). Based on the above photos, I think you may have the "D" form 9.3x72R. The case that would not fully enter the chamber is likely the "N" form case, since it is the one that is generally available now. The "N" form was intended as a compromise to allow one cartridge to be used in the other three rifles by a minor rechambering. Many rifles were so altered without the requirement to have them reproofed because the "N" form ammunition was loaded to the appropriate pressure for all and a bullet that is safe in various diameter barrels. If you run an "N" reamer into a "D" form chamber, you remove only a minimum amount of chips. If you have a "D" form chamber and don't want to rechamber it, if you dieform a "N" case and fireform it in your rifle, you can then load it using the common "N" dies (The chamber wall will prevent such expansion that the case won't chamber). You can physically size a loaded "N" cartridge in a 38-55 die so it will chamber, but you would need a file/trim die, or the type sizing die that holds the decaping rod in a separate threaded bushing, so that removing it will allow the bullet to pass through the die. If you do that, you will have to decide on your own to do it as I am not advising you to do it. Also, due to the 9.3 case being a few thousandths larger than 38-55, you can't, nor do you need to size it all the way to the rim. I hope this helps. It could still be one of the other cartridges.
MIKE

SKB,
A bullet that heavy would be OK for more modern 9.3s (9.3X57{M88}/62/64/74, etc.) but the standard bullet for the 9.3x72R N is the 193 grain Express type bullet. Formally other bullets were used such as 185 or 200 grain in jacketed bullets or in black powder rifles 250/260/280 grain lead (note, 9.3 jacketed bullets are too hard for 9.3x72R).

HalfaDouble,
The Lyman 366408 was one of the most common cast bullets for 9.3x72R and it served many people, especially those with black powder rifles. Many with nitro proofed rifles for lighter bullets were disappointed with this bullet's accuracy. This problem was often addressed by facing off the mold until it drops about 200 grain bullets. My favorite is the 208 grain H&G 512c, but this is no longer available. The rifles with .358-.359" barrels can use the 185-200 grain 35 Remington bullets or any of the various jacketed or lead pistol bullets. For slightly larger than .358 barrels, there was an old Lyman mold for 38 bullets thar dropped from the mold as 173 grain SWC .362" and would be useable in a great many rifles.

Mike

we have lift off.

Ordered a 4d reamer and re-cut the chamber, you guys were right it was a slight diameter/taper difference. Cut and checked the chamber with two live cartridges. Cut, extract, clean, drop round in... I didnt have to go full depth with the reamer. I stopped with 1/8" or so of the rim cutting portion behind the barrel face. I did it by hand and held the barrel in a bench vise

I definately recommend you to use a lot of cutting fluid and clear chip every 2 full rotations. Test fired two shots, measured the brass, no deformation, bulges ect. They measure very close to new brass. However it does seem the gun is off face as the primers definately show signs of flow. I'll post pics of those later

Another thing, what is the rim thickness on those S&Bs?