I am getting a new custom sako 280 ackley improved soon. Trying to get brass and dies. I see people talking about fire forming 280 remington brass. Some are even saying use cream of wheat. Can someone explain fire forming technique??

Why not just buy some Nosler 280AI brass?

Probably the best way to go. If you don't already own a .280 Rem and have a pile of brass on hand, why would you want to go through the fireforming process with it? If you need to buy brass anyhow, just buy the Nosler 280 AI brass and get to load development right off the bat.
As for fireforming, whether you use the Cream of Wheat method or simply load .280 Rem. brass with a mid to stiff powder charge of rifle powder and a .284 bullet, you're going to form that case to the new AI chamber dimensions which include a 40 deg. shoulder and minimum body taper. Buying the Nosler brass eliminates that step.

I just purchased a Cooper 280AI myself,and even though I have done some case forming in the past,it never crossed my mind to fireform 280 rem brass.I simply bought some 280AI brass,and I can immediately begin load development with no time and components wasted fireforming brass.

If you do end up forming your own I've had best luck with a faster burn rate powder and a mid range 280(not AI) load.

I also had a pard that tried to form nickel in his AI with poor results...

I believe Jarret loads ammo for this round too. Read up about his thoughts on it...

http://www.jarrettrifles.com/calibers.html

All you have to do when fireforming .280AI from .280 brass is simply shoot standard .280 loads in it. That way not only is it formed, but it's also fireformed precisely to YOUR chamber at the same time. I wouldn't buy the Nosler .280AI brass because of the higher price-even if it is better.

Is this from personal experience or from info BC posted a while back ? ...

Thanks for the info RR, good to know. I wonder what stumblejumper will think of them ? ...

I haven't had a chance to fire any rounds yet using the Nosler brass,but I have done some measurements to check consistency,and I was very impressed.I measured 20 rounds randomly,and the neck thickness was within .0015" in all 20 cases.I bought this brass after hearing many positive results from other people that had used the Nosler 280AI cases.I have however read that some early batches of Nosler brass were not nearly as consistent as later batches.As to the hardness of the brass,I will be firing some test loads in the next couple of weeks.