257 Roberts-forming from 6MM Rem or 7by57?

[Far North Hunter]

I can't find any 257 Roberts brass. I have read several comments on forming the 6MM up, as well as forming 7by57 down.
i have a custom 257 Roberts AI on its way.
I would really appreciate anyone's first hand experience on their best method.
Thanks in advance.

 

[David Emerson]

I can't find any 257 Roberts brass. I have read several comments on forming the 6MM up, as well as forming 7by57 down.
i have a custom 257 Roberts AI on its way.
I would really appreciate anyone's first hand experience on their best method.
Thanks in advance.

I would order some Norma 7x57 brass and neck it down. I will bet your reamer is based on that neck thickness. If you use 6 brass and neck it up you will get shoulder brass in the neck and get a doughnut.

 

[kiwikid]

My suggestion would be to order some Norma 257 Roberts ammo from the likes of Graf and Sons, they appear to have it in stock.
If your 257 Rob AI is chambered correctly you should be able to shoot the Norma ammo through it to fire-form your brass. It wouldn't surprise me if the accuracy of your 257 Rob AI is very good with the factory Norma 257 Roberts ammo.

 

[Edd]

You need to use 7x57 brass for forming 257 Roberts. Making 257 Roberts brass from 6mm Remington brass would be a project.

Buying loaded 257 ammo would be my choice.

 

[just_jon]

I just did a quick search and found brass at Midway, Brownells, MidSouth, and Grafs, however, given the price, i would agree with kiwi kid and Edd and buy factory ammo and have some fun shooting your new rifle. Cheapest in stock brass price I found was Nosler at Graf's at $1.56 each. Grafs has loaded Norma ammo for $1.95 each.

I ran into this same situation with my 250 Savage AI back in the dark ages before online shopping existed. Brass was not available at any price, but I got lucky and found five boxes of a Remington ammo from the same lot at a local gun shop. Accuracy in AI chamber was sub moa from my 15" T/C Encore pistol, so I spent an entire summer fire forming brass at the expense of the local groundhog population. I'm going to need new brass in the next year or so and plan on going the same thing only with Norma ammo this time.