Hi there, ok here is my little project I've been saving for. I got a MRI yugo mauser action. I got a new 8mm barrel. But the other day I got a good deal on some Redding dies for the 6.5/257 Robert's improved. I'm still gonna have someone make me a elk/deer rifle in the old 8x57 mauser. But I in the mean time what type of brass should I look out for for the 6.5/257 improved? What I mean is like if I happen to one day run into someone with 257 Robert's brass for sale to buy it or can I like turn 3006 brass into the 6.5/257 improved or what? These things I dont know. Just let me know what to keep my eye open for please. And just to let you know this project ain't gonna happen tomorrow, so I got time. Its probably going to be a 8mm mauser for awhile. Thanks.

No matter what you use, you are going to have to blow out the shoulder to the improved shoulder angle so you could use 257 Roberts, 7X57 or form and trim 30-06. May avoid blowing out the shoulder using the aught six brass, but will still need to fireform as the shoulder will likely be rounded.
ALL of my original 6.5X257 brass (which I still have) was aught six machine gun brass!
Depending on the specs of your dies and chamber you may or may not have to neck ream the 06.

The last that I formed and now am set for life was 7X57.

I would use 7x57; easier to get and necking down is easier than up. Not that up is hard, if you have never done it. Watch neck thickness, depending on your chamber size.

I use Remington Brand 6mm Remington cases in my 6.5-257.
I also use that same brand in my 7x57 ICL.
it fire forms the sharp shoulder better than Winchester etc does.

Reminds me of buying a stock and then having to go look for a rifle to make it work.

quote:

Originally posted by squeezenhope:
Reminds me of buying a stock and then having to go look for a rifle to make it work.

I built a rifle in 7x57 Ackley just because I got a screamin' deal on a set of dies.

What DPCD said. 7X57 brass will be your best bet. It seems much more available then 257 brass. You could make it from '06 brass, but that would be a lot of work. 7X57 would just have to be run through a die. I think it would be an excellent round.

I used Winchester 257 Roberts brass for my 257 AI 40 degree shoulder. But that was many years ago when you could find such things relatively easily.

Now, either 257 Roberts or 7x57 brass would be fine. I doubt you'll find 6mm Rem brass very easily (harder to find than Roberts brass).

A bit long winded but please bare with me...

l too built a 7x57 Imp' and had stated by forming from 7x57 sized brass, but they were coming up a tad short.... So, sitting at the bench and looking at the die sets on the shelf l formulated a plan of sorts.
.270win cases are near parallel through the body, and l have a shed load of Norma brass sitting waiting for a home.
l found that by running a .270win' through a .308win die to within 30thou of final size and then shortening the overly long neck before finally putting the case through the lmp die l could form 5 of the 7% from the start and the cases only took on a slightly rounded edge look from the final product. 1 thou' off the necks with an outside neck trimmer and you're done.
lf something like a 6.5x47lap' die could be found, you could form your cases from whatever brass of appropriate size and good quality you had to hand.

Or it's just that l like piddlin' about with odd projects to see where they lead...

I would use .270 Win brass. It seems no one locally reloads .270 so once fired .270 brass is cheap and easy to find at indoor ranges.
I would trim the length to be an exact fit to your chamber length. When the shoulder blows out the case will get .004 to .007 shorter.
Since the Obama panic began 6mm Rem, .257 Roberts and 7x57 have been rare to non existent and very expensive when found.

quote:

Originally posted by craigster:

quote:

Originally posted by squeezenhope:
Reminds me of buying a stock and then having to go look for a rifle to make it work.

I built a rifle in 7x57 Ackley just because I got a screamin' deal on a set of dies.

This is perfectly normal behavior. I once bought a batch of 10 chamber reamers (cheap), that have led to 6 rifles. I really only had interest in three of the chamberings. Figured I’d sell off the extras and recoup my money...

But a 6.5x55 is so good.

https://en.m.wikipedia.org/wiki/6.5×57mm_Mauser

Invented in 1893

.

6.5 x 57 Mauser brass is available at Grafs.

Prvi Partizan Brass 6.5x57 Mauser Unprimed
https://www.grafs.com/catalog/product/productId/73809

Is the 6.5/257 improved the same as the 260 AAR?

.260 A.A.R. (P.O. Ackley Data)
https://loaddata.com/Cartridge...-PO-Ackley-Data/6425

I suggest a reloaders that does not have forming die purchase one forming die, that would be the 308 W forming die. I also suggest if a reloaders with a 308 W forming die does not have a 243 W die purchase one.

And there is another forming die I can not do without, problem: I have never found another case former/reloader that could justify purchasing one, it seems folding and putting creases in the shoulder of cases is a better option.

Using 270 W and 30/06 cases when forming 7mm57 cases is a bad choice for rifles that are not military with generous necks.

I use 280R cases when forming 30 Gibbs cases. If the 30/06 cases is used the case will shorten from .040" to .050". the 280R cases is .051" longer from the datum/shoulder to the case head than the 30/06 case is from the datum to the case head. (when compared to the 270 case, the 30/06 and 270 length from the datum/shoulder to the case head is the same).

F. Guffey

I have a 6.5 Arisaka rechambered to 6.5/257 Improved. I use 6.5 x 57 dies to initially load 257 Roberts brass for fireforming. Then use 260 AAR dies to load the final product. There are so many variations of the 6.5 x 57 improved, but the AAR version dies work well.

The Arisaka has a light short carbine barrel with sporter stock and Lyman rear sights. It is also tapped and a Weaver rail installed for scope or red dot use.

Geoff

Kennedy, I am doing a Yugo Mauser also. I am going to shorten a 6.5x280 AI, .100". That will max out the length of a 140.

I was going to shorten a 6.5-06 by .050, but then I got this 6.5x280 reamer.

Thought about the 6.5x57 AI......but...., The Mauser case is a nice size!

It will make a good rifle!

I do got a handful of 6mm brass once fired. Maybe a bit over a 100.

quote:

Originally posted by Jgrabow6493:
6.5 x 57 Mauser brass is available at Grafs.

Prvi Partizan Brass 6.5x57 Mauser Unprimed
https://www.grafs.com/catalog/product/productId/73809

Is the 6.5/257 improved the same as the 260 AAR?

.260 A.A.R. (P.O. Ackley Data)
https://loaddata.com/Cartridge...-PO-Ackley-Data/6425

Grafs also have Quality Cartridge stamped 6.5/257 Roberts brass tho it's a bit pricier.