Best methods for fire forming w/o bullets

[wildcat westerner]

Howdy, A rifle I borrowed came back, a .257 AI without any cases. So, since I last fireformed a long time ago for AI cases I would like to form these cases correctly, and w/o bullets. What makes a very good substitute for bullets when fireforming so that shoulder gets quite sharp on the first firing?

Thanks, in advance,

Gene S.

 

[cahunter805]

This might get more responses in the reloading forum.
Without bullets you can size up the neck diameter and then resize and create a false shoulder. Then use pistol powder and cream of wheat as filler and plug the neck. The cases won't form 100% though.
I'd personally just get some cheap bullets and load them just to touch the lands and fire form.

 

[Pdvdh]

Here's a link to a thread I recently started. It's not the Encyclopedia Britannica. But it contains some useful information.

https://www.longrangehunting.com/threads/a-i-fire-forming-tip-of-the-day.194793/

 

[fordracer]

I use the cream of wheat or coffee works too. I do anneal the brass before fire forming
i am making 243 LBC out of 7.62 X 39 brass

 

[wildcat westerner]

Shooters, I did place this post in the wrong area, but still got the right answer. I have firefirmed a lot of cases, and yet received a combination of advice that is really much more complicated and so much better than, what I used to do years ago.
Thanks your combined, involved answers are obviously a superior way of forming consistent "improved" cases.
Thanks ever so much.
Gene S.