I know you can fire factory loads in the .223 AI chamber to form the brass, but what's a good load for fireforming primed brass and get a good, clean shoulder the first time? I don't want to waste a bunch of powder and bullets fireforming with full-power reloads and I have Herco, Unique, Trail Boss and AA-Scots 4100 that I can use with COW and a wax/soap plug in the neck.

Do an Archives search to find abundant info on fireforming.

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never mind.

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I had my first 223AI build 1996, I tried 8/9gr Bulleye/COW I got rounded shoulders didn't get the sharp ones like I did with the 222AI. 26gr/N-133 with a 52gr match bullet gave me groups in the .2's and thats was also my fireform load used a hart 1/14twist barrel 27" long barrel.

Heavy-for-caliber bullet, seated long, medium-weight charge of fairly fast burning powder (for that cartridge).

That's the hole concept with most all of the Ackley improved cartridges, you Can fire standard ammo in the AI chamber, still get good accuracy and be fireforming all at the same time.