98 KAR questions

[Eaglelord17]

Very interesting, almost reminds me of my Austrian 8x50r.

[Sentryduty]

What about 7.65x53mm?

[Sentryduty]

What about 7.65x53mm?

Wiki specs:

Specifications
Case type rimless, bottlenecked
Bullet diameter 7.94 mm (0.313 in)
Neck diameter 8.78 mm (0.346 in)
Shoulder diameter 10.90 mm (0.429 in)
Base diameter 12.01 mm (0.473 in)
Rim diameter 12.05 mm (0.474 in)
Rim thickness 1.00 mm (0.039 in)
Case length 53.60 mm (2.110 in)
Overall length 76.00 mm (2.992 in)

Americans would define the shoulder angle at alpha/2 ≈ 22.2 degrees. The common rifling twist rate for this cartridge is 280 mm (1 in 11.02 in), 4 grooves, Ø lands = 7.65 mm, Ø grooves = 7.92 mm, land width = 4.20 mm and the primer type is large rifle.

[Eaglelord17]

Interesting, and Belgium was using that round at that period of time, however wouldn't .318 be too large for it, as those used .311 bores

[Sentryduty]

however wouldn't .318 be too large for it, as those used .311 bores

I tend to agree, but with a quoted bullet diameter of .313" it's somewhat close. Based on the half cast visual angles and proportions, and the failure to close on a pulled cartridge leads me to suggest this as a possibility.

We have a similar angle of case neck and length, we have a shorter overall cartridge compared to an 8X57mm, we have a caliber that was in use as the time, and the bore slug could be a from a generous (loose) refit barrel or heavy use.

We have encountered Russian 91/30's with generous bores from time to time for various reasons. I am not 100% convinced of my own reasoning, but I think this caliber could be a good possibility, and worth taking some more specific measurements.

[vintage hunter]

wouldn't .318 be too large for it, as those used .311 bores

Bore yes, but if it's actually the groove diameter that's .318'' then that would be on the large side but probably still acceptable. I measured 5 Argentine 7.65mm bullets pulled from surplus rounds made in 1947 and the diameter is .314''.The groove diameters of German produced Argentine Mausers in 7.65mm generally run from .310''-.312'' while those made in house by the Argentines generally have grooves from .312''-.314''. As I understand it it's not uncommon to find Lee Enfields with groove diameters up to .316''-.318'' and they seem to give serviceable accuracy with .311''-ish bullets.

[Ruffasacob]

The only way to make an intelligent guess would be to have a full chamber cast. So I went back and got a full cast out. The chamber is definitely shorter than 8 x 57. my fumblings show a case about 52mm long. The nearest thing I can find in Frank Barnes "Cartridges of the World", is the 8 x 53 Mauser. That bullet is .318".
I'm no Mauser expert. What are opinions? This is not the original barrel?
If it's not, someone went to a lot of trouble to keep the same barrel contour, front and rear sights, etc.
Does anyone know what the mark under the barrel is?
Again, thanks to all for your insights.
Ruff

[Sentryduty]

While not an expert, I do enjoy educational discussion.

First of all the NRA proof mark ID sheet does not seem to list this mark, so no help there.

One photo I did find had a crisp "B" in a circle of a Mauser action, and suggested it was a Brazilian proof or ownership, I speculate that it could point to Argentina? More to follow, but just keeping the discussion ball rolling.

---------- Post added at 09:46 AM ---------- Previous post was at 09:38 AM ----------

Are there any other marks on the barrel aside from the circle A and the matching serial number?

[Paul S.]

I know next to nothing about Mausers despite owning two K98s. I wonder if the eagle on the underside of the barrel might be Polish. I don't know if this: http://www.ycgg.org/pdfpages/ww1/kar98a.pdf is helpful, but I'll offer it anyway.

[Eaglelord17]

I was doing some thinking on this, what if it was sent to the Ottoman Empire (Turkey)? They used 7.65, and that symbol on the barrel almost looks like a crescent moon with a star (which was the Turkish symbol).