doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Chanber casting question 9.3x72 Sauer?

I'm getting frustrated trying to get the cast out of the chamber. I'm using Cerro-safe from Brownells, it melts at 160-180 degrees F. Every time I use it I've had to apply heat to the outside of the chamber to get it out, which leaves me with a useless casting. Are there a few tricks that I can use?
I picked up a Imman. Meffert, Suhl, a few months back, 16x16x 9mmx72. the rifle bsrrel is stamped 118/35, 9mm 72 d. A 9.3x72 from 4 different manufactures will not slide all the way in, about 10mm sticks out. I think that it is the old 9.3x72 Sauer, but I would like to have a casting of it. Any suggestions will help, I'm stumped.
Thanks, Jerry

Yes, do not apply heat to get it out
I just cast a 12 gauge chamber and leade a couple days ago.

Here is what I did.
Chamber and lead very clean and dry.
Blocked the barrel just past the leade.
Heated the Cerro-safe
Poured it into the chamber area,
insured it did not cover the rim area of the chamber.

When the metal was hardened,
Using a wood dowel inserted from the other end of the barrel,
knocked out the casting onto a pile of old tee-shirts.
Used the flat of a hammer to knock the dowel rod.

Great casting

Different subject, the 9mm is .358 and the 9,3mm is .366
Your chamber marking is 9x72 so please used a dial indicator to mic the inside of the barrel at the muzzle and report back

As soon as it's solidified but still hot, push it out of the chamber.

It is under sized when still hot/warm and will expand some predetermined amt (5%?) to full dimensions when completely cooled.

If you leave it in the bbl to cool, it expands and is very difficult to remove w/o damaging it.



I usually take a cleaning rod w/ slotted tip. Put a patch into the tip and insert from the muzzle till it's an inch or so from the mouth of the chamber.

Warm the bbl chamber area to get good fill out. Doesn't need to be any warmer than 100F or so. Then pour the cast. Wait a few minutes for it to solidify and push it out w/ the attached cleaning rod.
Unscrew the casting w/ tip from the rod if it won't just pull off of the tip.

4-D Dies makes 9x72 Dies

9 x 72 $113.95

http://www.ch4d.com/

The 9.3x72R Sauer is a bottle necked case. I don't have my book with dimensions at hand but I don't believe there is any part of that chamber which is smaller than the regular 9.3x72R cartridge. The head diameter is definitely larger so the regular 9.3x72R would be a loose fit there.
I highly suspect that the 9x72R is the correct answer. A 118.35ga translates to a "Bore" diameter which will accept a plug gage of .340" but not one of .350" (108.45ga) which could be proper for either the 9mm or the 9.3mm. Gun was likely built prior to 1912.

Rifle Gauge Table

A brief table that is pretty helpful for pre-WWI German rifles shows the use of fractional 'gauge' numbers for barrel diameters. This was largest plug gauge diameter that would fit in the bore. The British proof law of 1868 had set up standard gauge sizes from .300" (172.28 gauge) to .450" (51.05 gauge) in .010" increments in the same sense that a shotgun bore is gauged, by the number of round lead balls of that diameter that make a pound. The Germans adopted this somewhat awkward system as well.

Gauge - inch
51.05 - .450
54.61 - .440
58.50 - .430
62.78 - .420
67.49 - .410
72.68 - .400
78.41 - .390
84.77 - .380
91.83 - .370
99.70 - .360
108.49 - .350 very common on 9,3mms
118.35 - .340 somewhat common on 9,3mms
129.43 - .330
141.95 - .320
156.14 - .310
172.28 - .300 very common on 8mms

These are most frequently seen with a / instead of the decimal point, as in 172/28 or 84/77

I pulled this from the German Gun Collectors Assoc.,so I'm not concerned whth the bore size, as you can see 118.35 is comon in 9.3's.
Just tried another shot at a cast, failed again, my plug was not tight enough. try again tomorrow.

Miller, I smoked up a empty RWS 9.3x72R case and it gets stopped at the front of the case. If the 9.3x72R Sauer has a slight bottleneck isn't this what you would expect?
Thanks to All, Jerry







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Jerry,
Did you mic the bore?

I feel sure a .357/.358 bullet is what you need.

If it is a true 9.3 the .357 bullet should fall through the barrel.

If you have an RWS 9.3x72R case, size the neck in a tapered 357 carbide die and let us know what happens.

Mike

Only on two conditions.
1; The case being tried is longer than the chamber dimensions.
2; The case being tried has a larger dia neck than chamber dimenaions.
Since both cartridges in question are 9.3mm & both have case lengths of 72mm, I do not see either of these conditions occuring. The 9.3x72R is a rather low pressure cartridge with relatively thin brass, it would not surprise me in the least to see that the neck dia of a 9.3x72R Sauer actually had a neck dia a few thousandths larger than the 9.3x72R. The fact that the Sauer case is bottle necked simply means it is bigger behind the bottle neck, not that it is smaller in front of it.
The 9.3x72R dimensions were originally established around lead bullets & even when jacketed ones began appearing they were jacketed with a soft thin jacket. Most have quite deep grooves which means the bore size is relatively small for the caliber. I would not expect a 9mm bullet to fall through very many older 9.3 caliber bores.

Not going to try another casting until I can get a more substancial knockout rod.
Measured the bore at the muzzle with a digital miccrometer .344 and .359.
Measured about 30 old rounds of 9.3x72R's that I have collected over the years, they are all over the map, .34 to .37?.
Reexamed and did some mearurements on the case I smoked up, it is larger by .005 at the rear of the case and that's where it's hanging up. Miller set me straight. Thanks.

What do you think about renting a 9.3x72R reamer and opening it up to the standard 9.3x72R?

Maybe this will help.