Correct. Most 5.56 and .223 out there can penetrate level III. However, to make it a point, when there’s ammo out there like XM855 available for purchase by consumers in addition to 5.45x39, rest assured those will be the first targeted by the politicians to be outlawed.
XM855 isn’t for penetrating soft armor. As already stated, any standard 5.56 round will penetrate IIIa soft armor or lighter. The primary reason the military designed the XM855 is to penetrate an old steel military helmets at 500 meters, since the ball they were using at the time couldn’t do that.
Federal (Olin) apparently has quite a bit of excess ammo in XM855 (SS109) from its Lake City Plant.
Within the last 4 months I’ve gotten two 30 cal ammo cans of it from WalMart of all places. They sold it for $175 for 420 rounds, packed in stripper clips - they even give you the ammo can and a stripper clip guide for the magazine.
A great buy! I saw the exact same thing ranging from $300-$400 at other places during that time.