JP Sauer Rifle

[Thomasg]

Hello All, I could use some help in identifying the model of this rifle and the caliber. Is this 7x57 Mauser?
Thank you for your help.
Sincerely,
Tom

[Thomasg]

A few more additional pics

[algmule]

Hello

Bore diameter

01-JPS&S-3.jpg

Peter

[mike ford]

Tom,
I don't think there is a model number for this rifle, but If I'm wrong it won't be the first time. It is a pre-WW1 sporting rifle as shown by the bore (not groove or bullet) diameter being shown in gauge measurement, which had been changed to millimeters by 1912. The 172,28 is often found on 8mm rifles and my guess is this rifle is chambered for 8X57I but, for sure, it is not 7x57. At the time this rifle was made, the Mauser patents were still in force and Sauer & Sohn used a commercial Mauser Oberndorf action (the Mauser serial number is the 3826 near the recoil lug, the 97602 is the Sauer serial number. The aperture rear sight is American and a type (I think Lyman model 35) that is sometimes seen on Sauer and Mauser Oberndorf rifles and is itself in considerable demand. It could have been installed in either the USA or Germany. After WW1, there were a great many surplus Mauser mod 98 type rifles available, and most firms used these actions instead of the more expensive commercial ones to build their rifles around.
Mike

[Thomasg]

Hello Gentlemen, First Thank you very very much for your replies. The bore diameter is in fact just a shade under .315". However I am faced with a real mystery. My 8mm Mauser head space gauges do not fit!
Mike you helped me tremendously with understanding the two sets of "serial" numbers. I suspected they were correct with regard to the matching bolt but had no education to back it up. Your a Star!
I also thought the proof marks were pre-1912.
Well a chamber cast will be done.
I will refer to the fine old arm as a "Sporting rifle".
Frohe Weihnachten euch allen!
Tom

[mike ford]

Tom,
I'm afraid a chamber cast won't do a lot to answer the question. In a Mauser, there is a variable space (around .200", give or take) and a chamber cast can't positively fill this space. You didn't say whether the bolt wouldn't close on a go gauge or would close on a no-go gauge. There are different answers for each situation. Will an 8x57 cartridge chamber? If so, I suggest you fire a round and use the fired case instead of a chamber cast (note: American 8mm Mauser cartridges are underloaded and/or use undersize bullets, so as to be safe in either size barrel). While you are at it, check to see if a .323" bullet will enter the case neck easily. If not, also check a .321" (32 Win. Special) bullet.
Mike

[Thomasg]

Hello Mike
No the 8mm Mauser head space (go) gauge would not fully go into the chamber and neither will an 8mm mauser shell. I currently have both 8x57I and 8x57 IRS and both casings stick out of the chamber by about 3/8".
Thank you very much for your quick response,
Tom

[mike ford]

Tom,
Does the bolt face look like it will fit a rimmed case? If so, it may be 8.15x46R. If that is not the case, try a 308 Win. case. If it almost fits, the cartridge may be 8x51. If neither of these trials work, check the chamber under strong light to see if a separated case body or some other obstruction is in the chamber (I once found a metal band from a ball point pen in a chamber). A chambering of 8.15X46R or 8x51 would be unusual, but not unheard of. If it all fails, I suggest you have the barrel removed (carefully) and then make a chamber cast to the end of the barrel and add the distance from the front face of the ring (inside the receiver) to the closed bolt face. While everything is apart, measure the diameter of the bolt face. Good luck.
Mike
Tom.
On second thought, before removing the barrel to make a chamber cast, try a 7.65x53 Round. The bore diameters were determined with "plug gauges" in .1mm steps and were not precise measurements. Some of the 7.65 rifles took .313" bullets and you reported above that the barrel is "a shade under .315".
There are tolerances built into everything manufactured. Sorry about the oversight.
Mike