You can use the Lee collet neck and seating dies for AI versions of the parent cartridge (270 winchester works for 270AI, 6mm Remington for 6AI).
This will work for a while till you need to full size. You can use the Lee dies while you Fire form a few cases and have a custom die made for full length sizing.
Or.
Redding makes a few AI dies available at Midway usa.
I use a Redding 6AI body die for body sizing and Lee 6mm Rem collet neck die, makes some of the most concentric ammo I can produce.