The Accurate Reloading Forums
making 257 Roberts brass
20 December 2017, 16:53
perrymaking 257 Roberts brass
With 257 Robts brass not being commercially available is there another caliber's brass you could convert? 6mm or 7x57?
Perry
20 December 2017, 17:40
zeeriverrat1You should be able to just run 7x57 brass thru your 257 rbts fl die and be good to go. You might need to trim them back a little.
20 December 2017, 19:21
dpcdMade a lot of them out of some 25-06 brass in the 80s. . But, the 7mm would require less trimming.
22 December 2017, 00:58
Atkinson30-06, 7x57, 6.5x57, 280, 270, to name a few can produce 257 Brass pretty easy..
My choice would be to purchase some PPU brass in 7x57 and run them thru the 257 Robts die, and outside neck ream, and trim to length, if need be.
I think HOrnady is making 257 brass now??
Ray Atkinson
Atkinson Hunting Adventures
10 Ward Lane,
Filer, Idaho, 83328
208-731-4120
rayatkinsonhunting@gmail.com
22 December 2017, 04:29
Ray BThere are 3 families of brass which will provide basic cases for about 3/4ths of the cartridges presently available on the US market. the families are .222, 30-06, 300 H&H. the crucial dimensions are the head diameter and sufficient length. A few cartridges not of these three groups are the rimmed cases, a few 6.5s, the 404 & 416 based cases. So to answer the question, any case that has a .473" base diameter and length of at least the 257 Roberts can be formed. this would mean 257 Robt cases could be formed from 7x57 and 30-06, but the 243,7-08, 308 cases would be short.
22 December 2017, 06:00
vapodogMidway has in stock 6.5 X .257 Roberts brass.....a real simple run through the .257 Roberts die and go to the range.....it's not cheap.....
You could buy loaded ammo as well.....Midway has Horbady, Norma, and Nosler ammo in stock.....the Hornady ammo is actually less than the cost of the aforementioned brass.....it's under $30 a box.
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22 December 2017, 06:25
vapodogGunbroker has a lot of new .257 Roberts brass at $1.00 each
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"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery."
Winston Churchill
23 December 2017, 20:00
StonecreekIt also works find to run 6mm Remington brass through a .257 FL die to expand the necks. The shoulder angle is very slightly different, but it still works fine.
I've necked down plenty of 7x57 to .257 and that is probably the best solution in that the necks will be just enough thicker to make a marginally better fit in most Roberts chambers. The same applies to 8x57 brass, but of course the amount of neck-down is somewhat greater and wrinkled or collapsed shoulders can be a problem. Using either case may require trimming for overall length.
Using .30-06 or that family of brass puts the neck of the trimmed .257 cases partially in the shoulder area of the old case. This usually requires thinning the necks after reforming.
27 December 2017, 23:52
Allan DeGrootSomewhere in my loading shop is a set of RCBS forming dies to make 6mm Rem, from basically anything long enough with a .473dia case head.
The set starts with an 7mmX57 form and trim then a 257Rob then a 6m/244Rem and includes an inside neck reamer.
But with the off again on again production of 7mmX57 Brass some here would regard using 7mm brass to be heresy!
I have not seen that set in years because my brother traded away his 6mm Rem Rifle and I have not bought another one.
I will eventually build one but On a Long (30-06) length action.
Because building a 6mm rem on a 308 length action is as much an act of profound stupidity as building a 7x57, 8x57, 257Rob or 6.5x55Swede on a short action.
If I provoke you into thinking then I've done my good deed for the day!
Those who manage to provoke themselves into other activities have only themselves to blame.
*We Band of 45-70er's*
35 year Life Member of the NRA
NRA Life Member since 1984
28 December 2017, 02:26
butchlambertI don't have a lot, but how many do you need?
28 December 2017, 05:59
leemar28quote:
Originally posted by Atkinson:
30-06, 7x57, 6.5x57, 280, 270, to name a few can produce 257 Brass pretty easy..
My choice would be to purchase some PPU brass in 7x57 and run them thru the 257 Robts die, and outside neck ream, and trim to length, if need be.
I think HOrnady is making 257 brass now??
How do you "outside neck ream" ?
Hang on TITE !!
28 December 2017, 07:13
dpcdYou know what he means.
For my Ruger 77, 257, it did not require neck reaming, or turning, as the chamber must be big enough to handle reformed brass. Once I got some real brass, in the 1980s, I no longer used the reformed brass.
30 December 2017, 03:26
model7LSSI have got a good bit of once fired stuff if you need some. Mostly Nosler, some RP.
Auburn University BS '09, DVM '17
01 January 2018, 20:53
buffybrI used to make them from military 7.62 blank brass.
NRA Endowment Life Member
Life Member Wild Sheep Foundation
01 January 2018, 23:02
NONAGONAGINWhat's the matter with just using 6mm Rem brass or is that is short supply or forgotten also...haven't checked.
LUCK

14 January 2018, 01:43
AtkinsonLemar28,
You use an outside neck reaming tool, Mine is from RCBS..I have outside neck ream my ,223 cases fir nt 6x45 that has a zero tollerence bench rest chamber. I also used it on some tight chambered 7x57s Ive had over the years and a few other calibers..I seldom however inside neck ream cases..
Ray Atkinson
Atkinson Hunting Adventures
10 Ward Lane,
Filer, Idaho, 83328
208-731-4120
rayatkinsonhunting@gmail.com
14 January 2018, 01:53
butchlambertquote:
Originally posted by Atkinson:
Lemar28,
You use an outside neck reaming tool, Mine is from RCBS..I have outside neck ream my ,223 cases fir nt 6x45 that has a zero tollerence bench rest chamber. I also used it on some tight chambered 7x57s Ive had over the years and a few other calibers..I seldom however inside neck ream cases..
outside neck ream- Outside turn maybe?