when fire forming brass by firing it in the gun' s chamber , do you have to have an actual bullet in the shell to keep the powder from spilling out , or can you just pack the front end of the brass with cotton or some other packing??

and if you can pack the front end of the brass , what can you use for packing material , ( for example ; cotton ) ???

it' s for a wildcat cartridge

I believe you will need the pressure. I can' t believe cotton will cut it. You can by cheap, I mean cheap cast lead ammo. You can even use something of a different size. Don' t go too crazy. Like a 243 in a 308win. That might be too small. Give it a try and let us know if it works. I really doubt it however. not sure what burnt cotton will do to a bore.

If you use a relatively small charge of a pistol powder like Unique, then fill the rest of the case with cream of wheat and use a wad of toilet paper or kleenex to fill the case mouth, it will fire-form well. Just do the firing outside, because it blows the paper and cream of wheat all over! Messy!!

Really? I am surprised it works. I figured you needed more pressure than that to fireform or at least push the shoulder up. Now I know

couldn' t that creamed wheat clog up the barrel , how often should i clean between case fireformings ???

What cartridge are you trying to fireform? I have had good results using dacron, tissue paper or cream of wheat or corn meal. **NOTE**...When using cream of wheat and corn meal make sure they do contain salt** I have used Alliant Unique and Bullseye for powders. The powder needs to be fast burning. Depending on what you are trying to do, the powder weight will vary. I have used from 10-20 grains. The case will not be completely formed until fired with a good load with a bullet. I made a pipe/muffler to use in my reloading room for doing the this type of fireforming, it' s quiet and contains the mess.
On simple fireforming, I think just shooting a middle of the road load with a cheap bullet is the way to go, it does save time.


AA

I regularly fireform 243 cases to 7mm-08 with excellent results,I use 10 grains of an old shotgun powder,pack the rest of the case with fine crushed cerial,compact it down then seal the case with candle wax then fire it in my rifle & I get perfectly formed cases every time.

You would have to experement initially to see how much powder to use,I started off with 5 grains but the case was only partially formed,10 grains of the powder I used works perfectly for me,also the faster burning the powder the better.

I thoroughly clean my rifle when i' m finished to get rid of anything that may be left in the bore or chamber.

It works great,the first batch of cases that I fireformed have now been fired 11 times & are still going strong.

Give it a try,you will be amazed,I was.

Alan