Commercial Obendorf Mauser rifle identification and caliber...

[Tagnar]

I have recently aquired an early Commercial Mauser, and I am having dificulty identifying the caliber of the rifle and the exact model. As you can see from the pictures it's marked Y, CrownB, CrownU, and marked 156,14 SR Serial number 299.

Based on my understanding - this would make the rifle an 8x57 (calibere 7.87mm). The challenge is - this should allow chambering of an 32/40 cartridge case... it does not. The case only goes in the chamber about 4/5ths of the way in. I understand some early mausers were chamberd in a 8x42 (not to be confused with the Kurtz round).

Any additional informaion on the age and model would be appreciated.

Many thanks,

Eric.

[mike ford]

Tagnar,
Your understanding that the bore(not groove or bullet) diameter of 156,14 ga., corresponds roughly to 7.87mm is correct. However, this only addersses diameter of the barrel,and not the nominal cartridge designation. Based on the form of your rifle(Kielerbuschen?), there is a better than even chance that it is chambered for 8.15x46R. A chamber cast is necessary to determine this, for sure. Based on the proof marks, your rifle was proofed between 1893, when proof laws became effective, and 1912, when they were changed to designate caliber by mm instead of ga. At this time, case length was added as a requirement, which would have helped you. While there was a 8x42, this cartridge would not be common for this form of rifle. I hope you find this useful. There was a recent two part article about 8.15x46R in WAIDMANNSHEIL, you might find it interesting.
Mike

[Axel E]

This rifle is a bit enigmatic to me and requires further research IMHO. Yes, there are the usual post-1893 proofmarks. On the other hand it is clearly marked "Gebrüder Mauser & Cie." = Mauser brothers and company. This was the name of the company from 1874 to 1884 only. In 1884 the company was renamed "Waffenfabrik Mauser KG". Maybe it was submitted to proof many years later than 1884 for some reason. Maybe Mauser simply used up an already marked barrel from stock about 10 years later or an old stamp on hand. The boltstop washer is certainly a makeshift replacement.
You certainly need to do a chamber cast to determine the chambering. Any originally smokeless cartridges are out of possibility. If the rifle is indeed of pre-1884 vintaage it cannot be a 8.15x46R too. It may be some else forgotten 8mm blackpowder cartridge.

[Tagnar]

The bolt washer is two tier on the OD, and inset with a custom screw, and both the screw and the bolt washer are serial numbered 99 - the last two digits of the serial number of the firearm (299), and the bluing \ petina match the rifle so I think they are original to the firearm. I have a fair amount of experience with wildcats, so I will take a chamber cast this weekend when I have time. Does anyone have the case dimensions for 8x46R and 8x42? ( Width at rim, rim width, length to shoulder, and width at shoulder?). I checked my Sharps guild on handloading - and while it has black powder and smokeless loads for 8x46R - it does not have case dimensions. If there are addtional pictures you would like of the firearm - please let me know.

[sharps4590]

Here ya go Tag, for the 8.15 X 46R

http://www.loaddata.com/members/sear...loading%20Data

[Tagnar]

Many thanks.... will post chamber dimensions when I size chamber this weekend.

[mike ford]

Tagnar,
Vic gave you the link for 8.15x46R, the head diameter for 8x42R would be around .468" and case length about 1.66". Of course, chamber dimensions should be a little larger.This cartridge was based on the rimmed version of the smokeless cartridge 8x57I.While I have learned that many strange things can be found, I still believe a 8x42 chamber in this rifle would be very unlikely. If Axel is correct and the cartridge is some other blackpowder 8mm cartridge from 1874 to 1884, it would likely have a head diameter of about .516" and a rim recess for the Mauser "A" base or "MB"base cartridge- about .595". Before the 8.15x46R, this was the most used case for this type target shooting. I'm looking forward to seeing what the chamber cast shows.

[Tagnar]

My guess is that the 8x46R is the correct case size, the rim size is slightly smaller than a 30/30 and 32/40 .. not larger. and the 32/40 case get's scratched at the bottom 1/4 of the case when inserted in the chamber - indicating it's to wide at the base... which would conform to the differences in the 8x46R case dimensions. A chamber sizing will tell for sure. Many thanks for the info.... The first response indicated that the rifle is a "Kielerbuschen", it was my understanding that rifles of this type are single shot, rolling block - similar to a Martini or a Remmington \ Browning action - and not a bolt action single shot as this one is. Do I missunderstand the classification?

Thanks,

Eric.

[Axel E]

A Keilerbüchse = boar rifle = a rifle for the "running boar target shooting" of the various German hunters associations over the years is a specialized target rifle stocked like a stalking rifle. The action type is unimportant here, but the rules for hunter's matches did not allow the use of full-blown Schützen-type target rifles. So crescent type, deeply curved buttplates, target peep sights, fully adjustable target type open rear sights and hand stops or -rests are expressly prohibited. Also, there are weight and dimensional limits. Keilerbüchsen were discussed several times in "Waidmannsheil". As your rifle has a deeply curved buttplate, a target rear sight and the base for a tang peep sight, it does not conform to the rules for a Keilerbüchse. So it is a Schützen target rifle. In Jon Speed's book "Mauser-Original Oberndorf Sporting Rifles", page 33, there is a photo of the Oberndorf Schützen target shooters club. Except the rifle of Paul Mauser himself all other rifles shown are target rifles on M71 actions just like your's.

[Axel E]

From Tagnar's descriptions up until now the rifle indeed appears to be chambered and proofed post-1893 for Frohn's 8.15x46R target cartridge, introduced about 1895. As the B U proofmarks and the gauge number appear to be stamped as an afterthought between older markings and the pre-1884 company designation on the barrel I would take a close look at both the muzzle and the breech end. Perhaps the barrel was converted by a liner to 8.15x46R post-1895 from a then outmoded older target rifle chambering and duly proofed for the first time by the Oberndorf proofhouse?

[Tagnar]

I believe you have hit the nail on the head... it's been rechambered.... When I first purchased it I assumed had been rechambered into .32 special or .32/40... as I determined it wasn't in a US caliber, I then abandoned that asumption, believing it was in a factory caliber and believed that the sleeving band was merely a difference left in the bluing from the crowning of the muzzle, - I excluded that from my discription above (Very sorry). The outline above makes for a marvelous storey, and an excellent bit of sluthing (realy appreceate it).

Does this\ would this particular variant carry any significant collectors value? (I have about $350 in it) if not - I may pursue rechambering it into .32/40 or .35 whelen. It would appear to make for lots of fun at the range (Already working on the Lathe on modifying a Lyman Post Diopter to fit the square tang mount port on the rifle) - if not for the caliber (8x42r isn't something I reload - could but haven't) I believe I would keep it.

[mike ford]

Tagnar,
I highly reccommend you keep the same chamber you have now. Whatever it is(if not 8.15x46R) we can make ammo for it. I don't think a 32-40 reamer will cleanup a 8.15x46R chamber, in the neck area. I form 30-30 cases with 32-40 file/trim die, before shortening and fireforming to 8.15. When I do this, there is significant expansion in the shoulder area. Rechambering to 35 Whelen, in my opinion, wouldn't be appropriate at all (pressure/length/rim considerations), plus it would have to be rebored and this might go through the liner(if any). Aside from all that, it just "belongs to be in a German caliber". This is still just my opinion, but it is your Rifle.
Mike

[Axel E]

I would not rechamber that rifle too. The sleeved barrel as is does not detract very much from the collector's value, as the sleeving/rechambering/proofing to 8.15x46R happened more than 100 years ago by now, between 1893 and 1912, as the bore size is still given as a gauge number. Any rechambering job would certainly kill a lot of that value. But it is your rifle, so you may do what you want. But forget any cartridge originally designed for smokeless powder, even the .32 Win Special! The M71 Mauser rifle with it's single locking lug against the receiver bridge simply is not strong enough for modern smokeless pressures. I have made many 8.15x46R cases from .30-30 brass. The 8.15x46R was the standard German target cartridge up to WW2. BTW, forget the "8x42" monicker! These rare numbers all don't fit your description. The half dozen different shapes of the MB base have a much larger base and rim diameter than the .32-40, base .516", rim .590". The later 8x42R "Mauser" was a smokeless, jacketed bullet number, also with a larger diameter, .470" base.

[mike ford]

Tagnar,
Axel mentioned 32 Win.Special as a cartridge to avoid especially.Look at the "sidebar" to the second part of the twopart article on 8.15x46R in "WAIDMANNSHEIL", for a description of the dangers of such a conversion. I'm looking forward to seeing the results of your chambercast.
Mike

[Tagnar]

Many thanks to those above... Chamber casting confirms that it's a 8x42R. So I sat down with my 32x40 dies and made a case out of a .32 special... sized the case down, trimmed it back to 1.83, dropped in into my lathe and trimmed the rim back to .484 and - the case drops in and ejects from the action fine... The Philip Sharps book on reloading recommends a case forming load of 4 gr of unique packed with wadding (He seemed to like wheaties...) and a cup of about 6500 fp... Does this sound right? any prefered load for fireforming?

Thanks,

Eric.

Eric