I just read the article on ss109/m855 being declassified by the BATF as armor piercing. Does that mean that it is legal in illinios, where ap ammo is illegal? or is that up to the state to define what is ap? also, i was told that there is a sunset clause (it will expire) on the 1994 ban, is this true?

Actually, M855 was never classified as armor piercing, since it doesn't meet the legal definition of AP.  The US military does not, and never has considered M855 AP - which is why it's marked with a green tip ("other") instead of a black tip.  The green tip is to prevent its issue/use with M16A1 1/12 twist barrels except in combat emergencies.

Why ATF specifically exempted it from the AP list is beyond me, unless it was to avoid confusion (not a step they take very often).

As to your other question, yes, the 94 AW ban sunsets automatically in 2004.  Our less optimistic members believe it will be renewed by congress, or replaced with something even worse and more restrictive before then.

Just to make it official, under the General Information section of the ATF Regulations Guide part 18 (Armor Piercing Ammunition) it states that 5.56mm SS 109 and M855 (Green Tip) and US .30-06 M2AP (Black Tip) are exempted from the definition of AP ammo and therefore exempt from the prohibitions imposed upon Armor Piercing Ammunition.

That's my $.02 worth.  I sell quite a bit of the Lake City and Winchester stuff and it's great ammo!