I have a drilling from Miller & Val Greiss. I don't know who built it for them, perhaps Sauer. The rifle chamber is stamped 6.2 (NOT 6.5) x 58 1/2. Also shows 8 gm bullet which would be around 120 grains. I've done a cerrosafe chamber and bore casting. Bore diameter is DEFINITELY .257 inches, NOT.264 inches! Other chamber dimensions are:
Neck; .296
Base: .456
Rim: .533
Case length: 2.30
In all respects, other than bore diameter, these are close to the specs for the 6.5 x 58R Sauer.
Barnes's Cartridges Of The World shows a bullet diameter of .264 for the 6.5 x 58R Sauer. Has anyone out there any knowledge of a 6.2 X 58 1/2R?

It almost sounds like a .25 Krag ...

Not a lot of 'standardization' in Germany back in the day, and they did love their tight bores. Dixon's "European Sporting Cartridges" does not show anything like a .257" version of the Sauer round.

It was also standard for the proof houses in Germany of that era to mark the bore (not groove) diameter; for instance a typical 8x57J would end up marked 7,7 or 7,8 x 57, not 8x57, while a 7mm Mauser would actually be marked 7 x 57 because 7mm (.275") is the bore (not groove) diameter.

Providing that your chamber cast shows the typical Sauer tapered case, I'd say your M u. vG was intended for the standard 6,5x58R Sauer round.

I reload 6.5x58R and the nominal diameter is .261. I shoot a cup and core from Delsing and Kerpen. Delsing passed away a couple of years ago and unfortunately the production of his bullets for odd calibers is no longer available.

Ron, I'll add also that regardless of what the intended chambering was, the fact that the groove diameter of your barrel is .257" makes it eminently shootable. Just neck size and seat with pretty much any .25 caliber rifle die set and enjoy!

Thank you all for your input. After letting the Cerrosafe normalize for a couple of hours, I remeasured and now get a groove diameter of .260". I'm in the process of machining a sizer die which hopefully will take 120 grain, .264" Nosler Partitions down to .260". We'll see how they shoot!!

I would think that 120 grain would just about be the sweet spot for this caliber. You should get a MV around 2250. I carry a 20 gauge drilling in this caliber and the 6.5x58R is just right for varmint we encounter when bird hunting. I'd have no problem with a whitetail at closer range.

My drilling is chambered in 6.5 x 58 R Sauer but the groove diameter is .260 right between any readily available bullet size. I've been shooting some very old Nosler Partitions that measure .262 but would rather have a correct size bullet for it. Guess I'll have to make a set of swage dies up and bump up .257 bullets.

Is there brass available here in the US? If so I haven't been able to locate any. Or better yet does anybody have a box or two of factory ammo they would sell?

Was able to get some boxer primed brass in Germany years ago. I have 35-40 older RWS Berdan primed if you would be interested. You can also resize 9.3x72R. Since Delsing closed shop, tough to get .260/61 bullets. I think Johanssen still may have them. .257 117grain bullets can often give surprisingly good acuracy.

I have 61 pieces of brass for sale for the 6.5 x 58R Sauer. I can sell to residents of Canada only, because of the restrictions on the export and import of components. This brass was formed from Canadian military .303 British, with headstamps: 1942, 1943, or 1944, DI Z. I took the following steps:
1. De-prime
2. Ream primer pocket to remove military crimp
3. De-burr flash hole, inside and outside
4. Lathe-turn rim to .500”
5. Lathe-turn base to .433”
6. Full-length resize in CH/4D sizer die
7. Polish in lathe to remove tooling marks
8. Neck-size in .257 Roberts die
9. Expand necks to .259” in CH/4D expander die
10. Anneal necks.
11. Polish in tumbler.
There are some oil dents and a few wrinkles on a few cases. These are purely cosmetic and will iron out upon firing. This is nice looking brass and is ready to load and shoot. My price is $5.00 Canadian per round, plus shipping. This price may seem steep, but you see the amount of work involved in producing it. The only commercial maker left is Bertram. Their brass would cost you close to $7.00 Cdn, landed, if you could find any in North America, which you won’t. I will sell in any quantity as long as you are willing to pay the shipping.

If interested, contact Ron Vella, at 905-723-7592, or mrrove@rogers.com.

Thank you.

Ron, I read your original post & grabbed Dixons book, originally thought it might be 6.2x58R Forster M12 pg107
bullet dia. .243
neck dia. .284
base dia. .4705
rim dia. .532
Then continued on to 6.5x58R Sauer GSP 18 pg 75
bullet dia. .260
neck dia. .287
base dia. .435
rim dia. .502
then went up to my ammo room & grabbed an original box of RWS 6.5x58R & measured an actual cartridge
bullet dia. .260
neck dia. .291
base dia. .426
rim dia. .499
I then read further down the post & see it looks like you have got it already figured out, decided to post what I had found in case it helps since I already had the info in front of me.

m4220

As info, here are a few photos of this drilling, the case and accoutrements that I assembled for it, the scope bases that I machined for it, and the sling that I made for it.

CH4D makes does to squeeze Bullets down. I use one to reduce .321 and .323 Bullets to .318 for my Cape gun.

Ron V - those cartridge cases look great!