Drilling Rifle Caliber?

[jillandsam303]

Just got a new drilling that is proofed "6.4x55" in September 1923. I'm having a chamber cast made since several pros have suggested it might actually be a rimless 6.5x54 Mannlicher Shonauer. But why the "6.4" and "55" stamp? Any ideas?

[Axel E]

Already answered your question to Dietrich Apel by email on Nov 4. Hereit is again:
6.4 mm is not the groove or bullet diameter, but the land/bore one, ok for a 6.5 mm, .257 - .260" bullet, but a bit narrow for a 6.5 Mannlicher or Swede, 6.7 mm / .264" bullets. 55 mm was the max allowable case length. You should make a chamber cast before trying any cartridges. Another possibility may be the 6.5x53R rimmed Mannlicher, today CIP minimum land diameter 6.48 mm (this would match a "6.4" stamp), max case length 53.59 mm.
But in the 1920s barrels were often a bit tight by today's standards.
Is the Extractor for a rimmed or -unusual- for a rimless case?
Without any chamber dimensions, taken from a chamber cast, I have no idea what cartridge may fit your chamber.

[jillandsam303]

Axel, thanks again. The gun is definitely for a rimless cartridge. It has spring loaded pins in the extractor to grab the rimless cartridge. I'm having a chamber cast done.

[Axel E]

As I know now the drilling is set up for a rimless cartridge , the max case length is given as 55 mm and the 1923 standard bullet weight is given as 10 gramm = 154 gr, my guess now goes to the 6.5x55 Swedish Mauser. The now CIP min land diameter for the 6.5x55 is 6.5mm, but bore dimensions were not yet standardized by 1923. A barrel stamped "6.4 mm" may have been as large as 6.499 mm. A 6.5mm cylindrical plug just did not pass the bore at the proofhouse. Waiting for the results of a chamber cast is still the best option.
The 12 gauge chambering and the use of a rimless rifle cartridge are both rather unusual for a pre-war German drilling. The drilling may have been made for the Scandinavian, Swedish or Norse, market originally. The pointer + European hare and European squirrel game scenes also point to the Sweden direction. Americans were not the only ones who ordered elaborate guns from Suhl. As the gun is not signed, "Fred Adolph" and "Kornbrath" are pure assumptions. Very often Suhl engravings are labeled "Kornbrath" by Americans, but a German engraver can easily distinguish a Suhl engraving from Kornbrath's Ferlach trained style.

[mike ford]

jillandsam303,
There is enough difference between the diameter of the 6.5x55 Swedish case head and other 6.5mm cartridges, you may be able to verify Axel's ID of the chambering by measuring the diameter of the head area of the chamber itself. This way, you wouldn't have to make a chambercast. If you don't have the tools to take precise measurements, any Gunsmith or machine shop could do it for you. You should expect the chamber to be slightly larger than the maximum cartridge diameter.
Mike

[Nathaniel Myers]

If you would, I would like to see how the rimless extractors are set up for the rifle chamber. And of course, would like to see the complete drilling.

[jillandsam303]

Axel, as usual, your knowledge and help are impressive! Interesting about the type of animal engraving pointing to a particular country. I'll let you know what the chamber cast indicates. Is there any german engraver who might be able to pinpoint who did the engraving if not Adolph or Kornbrath? Or does the type of action give us some hint to which manufacturer may have made this weapon in 1923? I'll send more photos if that will help. Again, thanks so much for your time and assistance in determining the origin of this gun.

[jillandsam303]

Nathaniel, here are a few pix of the extractor pins and the wonderful engraving 49224a11x4.jpg49224a11x5.jpg49224a11x6.jpgP1100384.jpgP1100386.jpg

[jillandsam303]

Mike, thanks but I don't have the tools to perform this measurement. I'll have to wait for the Chamber cast. I hope it is 6.5x55 Swedish. I like that caliber and it should be easier to get than some of the other 6.5s. Thanks again.

[mike ford]

jillandsam303,
Remove the barrels, chamber the cartridge and place a straightedge across the cartridge/extractor/barrel. If it is ,indeed, flush and the action closes on an empty chamber; I don't understand. If however it is not flush, check to see if the extractor has some "trash" under it, check to insure the spring loaded pin in the extractor has been turned and doesn't fit the extractor groove in the cartridge. If this all checks out, carefully smoke the cartridge with a candle or lighter and try to chamber it again. Close it a couple times and remove the cartridge, observing where the interference is. It is important to use a factory cartridge for these tests ( once you get it "squared away", however, carefully loaded handloads will be fine). BTY was the new firing pin installed with a bushing in the breech face? If so is it flush? If so, is the firing pin flush or below the breech face when it is cocked? On second thought, you should check the firing pin before closing the barrels on a loaded round( or do it outside with the drilling pointed in a safe direction). Let us know how the "checks" turn out.
Mike

[Nathaniel Myers]

Are you sure it is 6.5x54 MS? I understand you measured the casting, but is that the closest cartridge or is it difinitively 6.5x54MS?

One other thing to consider, if you make a dummy round, and try chambering it, is the bullet and bullet seating depth.

I recently had a 318 Westley Richards reamer made for a customers project. Got the barrel chambered, everything dandy, and low and behold a round will not chamber. Wound up sending it back to the manufacturer. They claimed it was made accurately to CIP specs. However the throat was not correct for the bullet I was using ( i.e. Customer dummy round). I was told this was a common problem with European cartridges and American bullets. I of course tried to explain to the gentleman that Kynoch manufactured ammunition was not American , and no one in the US loads that ammo.

Anyway, point being, try a piece of correctly sized brass. And as Mike pointed out, check with lamp black (sharpie works too) where the cases is binding.