Q. But isn't M855 ammo Armor Piercing (AP) and illegal to possess for non-law enforcement? Isn't M855/SS-109 restricted to military/law enforcement use? Isn't SS-109 illegal in Illinois?
No... no... and not as of July 26, 2002.
Some states may regulate it, but Illinois doesn't. We're not sure how that rumor got started. This comes up quite often because less than ethical suppliers try to use the marketing punch of "armor piercing" to sell more of their ammo. Since M855/SS-109 is more expensive than M193, some dealers go to great lengths to pawn it off. It is true that M855 was designed to increase penetration at longer ranges (500-600 meters) primarily to deal with the SAW issues, but don't mistake this "enhanced long-range penetration" design for "armor piercing." M855 is officially considered "ball," or standard ammunition by the military.
Fact: "Armor piercing ammunition" is defined in federal law [18 U.S.C. 921(17)(B)] as "a projectile or projectile core which may be used in a handgun and which is constructed" of various metals harder than lead, or "a full jacketed projectile larger than .22 caliber designed and intended for use in a handgun and whose jacket has a weight of more than 25 percent of the total weight of the projectile." SS-109 bullets used in M855 have a steel tip under the jacket, but they have a lead core.
As if this were not enough BATF has specifically exempted M855/SS-109 along with .30-06 M2 AP.
Straight from the horse's mouth (ATF):
NOTE: THE FOLLOWING CARTRIDGES HAVE BEEN REMOVED FROM THE DEFINITION OF ARMOR PIERCING AMMUNITION:
5.56MM (.223) SS-109 and M855 Ammunition, Identified by a green coating on the projectile tip.
US .30-06 M2 AP, Identified by a black coating on the projectile tip.