Don’t waste good bullets! I fireformed my 280 AI for years, but now use Nosler.
As others have said, point the barrel straight up. I use ~ 12-15 grains of bullseye pistol powder. Instead of cream of wheat, I use a quarter square of toilet paper tamped down hard with whatever will fit down in the case neck. The tp will hold the powder in position just fine.
Word of caution: Bullseye will heat up the barrel fast. I FF about five rounds and give the barrel a rest, or pour cool water down the bore to help. I just don’t like the idea of frying my barrel with twenty straight shots, but that’s just me. I could be wrong about frying it, but elect to be cautious.
It’s worked for me since about 1990.
I don't see how fire-forming with maximum standard .280 Remington loads, and bullets you plan to hunt with, "wastes" those bullets. Instead, I have found that many improved rounds shoot very well with "standard" loads and "unimproved" brass right from the get-go, which doesn't "waste" any more bullets than standard load work-up. You're also gaining info AND fire-forming brass during each range session.
I also have generally used Nosler .280 AI brass--or Norma brass, since they were making it for Nosler when the .280 AI was first accepted by SAAMI. But must I sold my last .280 AI a few years ago, partly because I could never see any real difference between it and various similar cartridges in the field, and the others didn't involve fire-forming, or trying to find more expensive brass, especially during the periodic shortages that keep occurring.
But whatever....
