A buddy of mine just inherited a Turkish Mauser and a bunch of reloading equipment, and he has turned to me to help him reload for it. I've never loaded for 8x57, and after doing some research on the round, I'm more confused now that ever.

In his pile of reloading stuff, he has 3 different lots of bullets, all of which measure a 0.323" diameter. If I understand it correctly, that is the "newer" 8x57 diameter that came out post-WWII. Interestingly enough, he also has some seemingly brand-new R-P 8mm Mauser cases, and the ID on the case necks is 0.317" which corresponds to the older diameter.

Several questions...
1) Would a "modern" sizing die (i.e. Lee, RCBS, Hornady, etc) resize the case neck to a 0.317" ID or a 0.323" ID?
2) Does any newly made brass come with the 0.323" ID necks?
2) Were Turkish Mausers made in 0.317" ID, 0.323" ID, or both? If they are both, should I worry about measuring the actual ID before selecting a bullet for him to reload?

Also, I would appreciate any advice and/or reloading resources for the 8x57 in a Mauser. I really want to learn!

Thanks all!
Nick

You asked relevant questions.  Re; #1.The modern dies will properly reform the R-P cases.  You know, I presume about using case lubricant on the cases & in the inside of the case mouths.
Re: #2.  I don't know.  But it doesn't really matter.
Re: #3.  Learn how to properly slug the bore of than rifle.
Then measure the bullet's larger out side diameter with good caliper that measures to the .001 or micromoter.
That will resolve your question.

Slugging the bore is a must. If you aren't comfortable in doing this yourself a local smith can do it for you quite easily.
Once you know the grove diameter, you can decide the diameter of your expander ball. If it comes out to .323 I'd get an expander .001 to .002 less than grove diameter. If .318 diameter I'd go to .317.
You may have to polish your expander with a piece of Crocus cloth to get it to proper diameter.

The German Army adopted the 8X57 JS (.323) in 1905. If your rifle was made before then have it checked by a gunsmith to see what the bore dia is. Dies and brass made today will before .323.

Thanks for the info, gang.  I'm definitely going to slug his barrel, so we know which diameter it has.  That being said, I'm fairly certain that it's a post-WWII rifle, so it's 0.323.  Can't be too safe though.

Thanks again!

Nick

Commercial ammo makers may use a .318 bullet in case someone has an older rifle with the smaller bore. This is a CYA action by the ammo makers. You can imagine what would happen if you fire a .323 bullet through a .318 bore.
ETA–– most commercial 8mm Mauser ammo is loaded pretty weak to help mitigate the small bore problem also. Your reloads are going to be more powerful than the factory stuff. Thats what I found when I started to reload 8mm Mauser.

Turkish Mausers have the bore diameter stamped right on the barrel in front of the reciever under the handguard.  If it is 7.90-7.92 you have the larger barrel groove diameter and slugging is not needed.  If the gun has a half moon cutout in the front reciever ring to allow the bullet tips to clear you have one of the older small ring turks and you might want to stay away from the very maximum loads in reloading manuals such as Speer that load the 8mm to its full European power specification.  These guns were designed for the 7.65 Mauser and were later converted to the longer 8mm and are not as strong as the newer 98 Mauser actions, but were used for years with the full power Turkish 8mm ammunition.

If the reciever is dated 1938 or later and is stamped K.Kale it is probably a large ring 98 style reciever with small ring barrel threads so the Turks could use up all the spare barrels from their older guns.  These are structurally as strong or stronger than the regular Large ring Mauser and will handle the maximum loads easliy.

I reload for my 8mm Mausers, but I usually just pull the bullet from surplus Turkish ammunition and average the charges of about 5 then recharge it into boxer cases and seat softpoint bullets to make hunting ammunition.  At the time I bought this ammo it was about 5 cents per round so it is cheaper for me to pull the bullets for the powder than to buy new powder.  I then take the FMJ bullets and corrosive primed cases and load them with about 15 grains of Unique and make plinking loads with them that are much easier on the shoulder and quieter to boot.