Where do I find info on this caliber? I have several books but no info on this.

The "6.5 Roberts" was pretty popular in the early years after WW-II. Many "liberated" 6.5 Japanese rifles were rechambered to use this commonly available case because the cases/ammunition for the Ariska were difficult to come by.

I have a Speer manual No. 7 (copyright 1966) that lists loads for this and what it also interchageably calls the 6.5x57 Mauser. Bullets weights are 87, 120, and 140, and powders all of the IMR series powders plus H-570 and Hi-Vel No. 2 (how useful!) are listed, as is H 380.

As I am a dedicated Luddite, I don't know how to scan anything into my computer, but if you can't find this old manual, tell me which powders and bullet weights you are interested in and I'll quote you some loads.

To pick an example, the manual is showing a "maximum" of 46 grains of IMR-4350 under a 120 grain bullet for 2755 FPS. The test rifle is a BRNO Mauser with a 24-inch 1-7.5 twist barrel. Now, since I used to get 2900 fps with a 120 grain bullet in a standard .257 Roberts with sustainable pressures, I've got to believe this data is very mild, which is understandable since the Speer technicians knew they were dealing with thousands of non-standard rechambered rifles on which the gunsmithing might be suspect.

I shoot one....

if you can't find load data... 6.5 x 55 load data is pretty interchangable....you can work up from there also, since there isn't any real SAAMI specs for it...

you can also use 260 Rem Data also... just don't start at max, depending on the brand of brass you use...

both will give pretty close performance to the data of the other two cartridges..

start lower and work up tho toward the maxes...

What's the difference between a 6.5 Roberts and the original 6.5x57 mm Mauser from 1900 or so?

quote:

Originally posted by DUK:
What's the difference between a 6.5 Roberts and the original 6.5x57 mm Mauser from 1900 or so?

There can't be a lot of difference IMO.....

I'd certainly be willing to work up loads from there!

there is a article in this months reloader mag about it.

quote:

Originally posted by vapodog:

quote:

Originally posted by DUK:
What's the difference between a 6.5 Roberts and the original 6.5x57 mm Mauser from 1900 or so?

There can't be a lot of difference IMO.....

I'd certainly be willing to work up loads from there!

Reverse engineering back to the mother cartridge?

duk hit it on the head...
it is simply a 6.5x57. i like the cartridge alot. i had one built in AI., shot it for a while, then had the gunsmith push A 6.5X.270AI. reamer in the chamber. after all the hassle of having a reamer made so that the new chambering wasn't the same as a basic 6.5-06, found it wasn't worth the expense. the 6.5x57AI did just as good in every respect, i would think, if compared to the 6.5-06, one would find the same thing. what's worse is that i ended up with a really fickle "wildcat"(if you want to call it that) that didn't really like anything. i think the longer, '06 cased version (esp. in AI) is just too much cartridge capacity for the 6.5 bore and wish i had the shorter cased version back. that 57mm. case is just plain perfect for the 6-7mm. bores. i might have it done one of these days! one thing to consider is that the 6.5 rem. mag is known as a throat smoker, so that will give you something to think about.
redding makes the dies i have and they are nice. i would strongly recomend the AI. version. that little increase in powder capacity helps out with the heavier bullets.

quote:

Originally posted by DUK:
What's the difference between a 6.5 Roberts and the original 6.5x57 mm Mauser from 1900 or so?

The Roberts case and the 7x57 case are identical except in neck diameter. The 6.5x57 can be made from either.

However, in the 1950's when this cartridge conversion became popular in the U.S., there was plenty of .257 Roberts brass available, while the 7x57 was considered an exotic and virtually obsolete cartridge (my, how times change). Simply because Americans were much more familiar with the Roberts and brass was headstamped "Roberts", the name 6.5 Roberts became the popular label for this cartridge.

In Europe such a name would seem silly. I suppose if the British had been doing these conversions of Japanese rifles they would have called it the ".263 Rigby" . Err . . . make that the ".256 Rigby"

The 6.5x55mm case head is the only Mauser case head not .470", but .480" instead.

The loads are so wimpy, the American companies just make their brass on the regular .470" machinery.

But European brass is .480".

The Sierra 5th Edition Manual has a section on the 6.5X57 Mauser. I can quote you some loads from this if you need them. I load for the 260 Bellm #2 (6.5 X 444) and this is the closest that I have found to being dead on. I am sure that your 6.5 X 257 Roberts is almost identical to the 6.5 X 57 Mauser.

Load data for the 6.5 x 57 is the same for the 6.5 Roberts...

however the two cartridges DO HAVE different shoulder angles...

a 6.5 x 57 will chamber a correct 6.5 Roberts cartridge, but a 6.5 Roberts correctly dimensioned, will NOT chamber a 6.5 x 57 cartridge...

but load data with the 6.5 x 57, the 6.5 x 55 and the 260 Rem are pretty much the same... in fact I filled all three once to the rim with H 380 powder and weighed each charge and they all came out exactly the same!

but that was using Win 257 Roberts brass, Win 6.5 x 55 Brass and Win 7/08 brass necked down to 260 Rem...

a Rem Case in 257 has less capacity and heavier side walls than does Rem Brass....
same with the 6.5 x 55 Win brass has more capacity than the Rem 6.5 x 55 Brass...

the 6.5 x 57 is my favorite cartridge for non varmint hunting...for deer and elk...

Thank you guys for all the great info.

quote:

Originally posted by tnekkcc:
The 6.5x55mm case head is the only Mauser case head not .470", but .480" instead.".

Which perhaps relates to the fact that the 6.5x55 is neither a Mauser design nor is it a Mauser case.

Regards

quote:

Which perhaps relates to the fact that the 6.5x55 is neither a Mauser design nor is it a Mauser case.

The 7.5 Swiss and 6.5 Swede both. What are they then?

quote:

Originally posted by 303Guy:

quote:

Which perhaps relates to the fact that the 6.5x55 is neither a Mauser design nor is it a Mauser case.

The 7.5 Swiss and 6.5 Swede both. What are they then?

The 6.5x55 was a design by the joint commission of Sweden and Norway dated to 1891.
The Swedish subsequently adopted the Mauser M-94 rifle for the new cartridge design whereas the Norwegians adopted the Krag-Jørgensen.

Thanks for that GBF. So where did the Swiss get there cartridge? Did they adopted a necked up version of the Swede or the other way around?

quote:

... but load data with the 6.5 x 57, the 6.5 x 55 and the 260 Rem are pretty much the same... in fact I filled all three once to the rim with H 380 powder and weighed each charge and they all came out exactly the same!

You had me worried there for a while seafire2. Then I measured a few cases for myself and realized you said you measured to the rim! I measured to the base of the neck and found the 6.5 Swede to be surprizingly large! Larger than the 8x57 (all I have) - in fact, getting close to the 30-06! (Well, halfway between the two anyway). Quite a bit larger than the 308 (again, all I have). How far into the case does the 260 bullet normally seat? I always thought the 6.5x57 and the 6.5x55 had the same capacity. Not when measured to base of neck! Oh, I have a European case (or two).