Thread: 257R Experiences

Originally Posted by tetawa

Still having fireform problems, can I buy 6 unfired 257R cases off someone to check measurements, gunsmith recons he put the correct "crush" for the standard 257R to chamber. All my brass is 6mm or 8x57 which I have resized.

I would help but only have reformed cases too. Mine miss fire if I oversize them. Mine need to be firm on closing to get reliable ignition.

Originally Posted by Tahr

I would help but only have reformed cases too. Mine miss fire if I oversize them. Mine need to be firm on closing to get reliable ignition.

I run them thru a 6.5 neck die then resize 2/3rds of neck to 257, still get unreliable ignition, have zero problem when they have been fire-formed to 257 Ackley.

Originally Posted by tetawa

I run them thru a 6.5 neck die then resize 2/3rds of neck to 257, still get unreliable ignition, have zero problem when they have been fire-formed to 257 Ackley.

Oh. OK. Didn't realise yours is an Ackley.
I just go straight from 6mm rem/7mm Mauser to .257 in one go.

Originally Posted by tetawa

I run them thru a 6.5 neck die then resize 2/3rds of neck to 257, still get unreliable ignition, have zero problem when they have been fire-formed to 257 Ackley.

Like you I would have thought that crushing down on a whole 1/3rd of the neck would have been sufficient to hold things in place. Do you recall I initially had problems back in 2021 in the final 6.5—to—.257 improved step when I had annealed prior. The brass was too soft in combination with only 0.007" or so of false shoulder. Options were to use a larger diameter shoulder or defer the annealing, and fortunately the latter worked. Maybe you'll need to go the other route and use a larger diameter if the neck is already a bit soft?

Originally Posted by Puffin

Like you I would have thought that crushing down on a whole 1/3rd of the neck would have been sufficient to hold things in place. Do you recall I initially had problems back in 2021 in the final 6.5—to—.257 improved step when I had annealed prior. The brass was too soft in combination with only 0.007" or so of false shoulder. Options were to use a larger diameter shoulder or defer the annealing, and fortunately the latter worked. Maybe you'll need to go the other route and use a larger diameter if the neck is already a bit soft?

Yes, I had them annealed before resizing, think the problem was there before as I tried some cases which hadn't been annealed. The more neck that is left oversize doesn't help with neck tension on the projectile to jam into the landes

I have never found a jammed bullet to be of any use whatsoever regardless of neck tension, though most reports on fireforming always list it as an option. With soft brass a larger diameter false shoulder on which to crush might be the only way forward, perhaps a significantly larger diameter?