doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Litte OT: to use 8x57js in 8x57jrs

Hello gentlemen:

I friend of mine is about to purchase a nice Merkel combination gun caliber 8x57 jrs over 16ga. Not sure of the model, bus seems to be a 200E, made in 1954.
The problem is that the only ammunition available here is the 8x57 js (8x57 Mauser made by Selier & Bellot) and the rifle barrel is marked 8x57 jrs

Someone (perhaps factory made because is very well done) made an extractor for a rimless cardige so the gun have 2 extractors, one for the rimmed and one for rimless.

Please give me your advise: such change is possible?
Can you fire 8x57 mauser ammo in this rifle?

Because the nice done rimless extractor it seems that someone that knows made the adaptation (at least the seller tell us that) and is safe to use the rimless ammo, but I am sure that you can give me a correct advise regard this technical matter.

Best regards,

Jose

Jose;
Hopefully someone more knowledgable than me will come in with better info than I. As I understand it though the two rounds should have identical chamber dimensions except for the rim. There would be no danger created by the lack of the rim on the js rounds. The main point of concern here would be to ensure the chamber was cut to properly headspace the js as the jrs headspaces on the rim.
Another point & this one I am totally unsure of, but I seem to recall seeing at some point in time that the rimmed versions of these Mauser cartridges were often factory loaded to slightly lower pressures & balistics than were their rimless counterparts intended for use in the bolt actions.
The headspace issue is quite easily determined by use of a headspace gauge. Again hopefully someone with more knowledge of the pressure levels of the two will chime in. I do know that for many years the US loading of the 8x57 round was quite mild in defference to the many old 88 commission rifles kicking around, most of which did not have the S-Bore. Assuming correct headspace in the chambering this ammo would be lower pressure than even the jrs rounds so should be completely safe.

Yes, Jose, the friend of yours can use 8x57js ammo, moreover extractor for rimless cartrtige allready made. By theory 8x57jrs would be more accurate on target in 8x57jrs chamber, bit its theory only.

If you can get RWS ammo they make 8x57JRS. Lagopus.....

8x57 JRS


8x57 JS


Pete

Gentlemen:

Thank you for your replies.
It is good to know that you can safetly shot js ammo in the jrs chamber (with tha apropiate rimless extractor).
The only available cardige here is Selier & Bellot 8x57 Mauser (js) with a FMJ, 190 grains bullet.
Geno: I hope my friend read your reply and convince himself. The rifle-shotgun are very intresting and, I think, in a good price: Merkel 200E, 2 set of barrels, 16 over 16 and 8x57 jrs over 16, scope bases, scope rings and an old weaver 2.5-4 x scope, all in a nice case for $3,500 USD
What do you think?

Best,

Firing the .318 dia. bullet in the .323 dia. (JRS) bore could allow gas cutting as it leaks around the smaller dia. bullet. You can get the ammo you need--better to use as designed. Steve

Note the questioner referenced firing JS cartridges in a JRS chamber. Bullet dia would not be an issue here as both have the .323" bore. 8x57 J & JR have the .318" bore, the S designates the .323" one.