No, body armor, according to Massad Ayoob, is legal to purchase and wear in all 50 states unless you are a convicted violent criminal or drug trafficker, or are committing a violent crime or drug trafficking.
Second Chance makes comfortable, lightweight concealable body armor that fits like a sweatshirt under your clothing. You may have some difficulty purchasing from them unless you have a character reference from someone in law enforcement, a CCW permit from some state, or some other indication that you're a card-carrying good guy.
A couple of points about these HCI losers (/oxymoron):
1) Changing a ballistic "fingerprint" is incredibly easy - change the firing pin and barrel, or fire-lap the barrel and change the firing pin, or just fire the gun a few hundred times with several cleanings in between.
2) How about bullets fired from a saboted round? Get a sabot that is .308 in diameter and fire a .223 bullet - I guarantee you that there won't be a single mark on the bullet from the rifle used.
3) Criminals who are as disciplined and intelligent as this sniper (who is, just for clarification, an evil SOB that is absolutely devoid of any morality), won't be caught by any such system. They will either take the steps listed above to make the bullets they fire untraceable, will pay some underground gunsmith to do it, or will steal someone else's highly-accurate bolt gun (or pay a fence to get one). In short, this is another scheme to make the law-abiding pay for the crimes of criminals and/or the mentally deranged. No one should be surprised.
4) This scheme, even if it COULD work like human fingerprints, requires the ballistic "fingerprinting" of every gun in the US. Again, we have a back-door registration scheme (no surprise there); also, that couldn't possibly work, since there are tens of millions of guns that were never on 4473s (pre-1968 guns, war trophies and guns brought into the country "illegally" by the mafia, drug gangs, etc.)
5) The biggest point is that these HCI Dassholes are concentrating only on guns. What about other means of killing people? Does ANYONE recall that the largest mass murder in US history was accomplished using about $1.00 of gasoline in NYC in 1990? To refresh memories, some wacked-out imbecile was P.O.'d at his girlfriend after an argument, so he made a Molotov cocktail and tossed it into the Happy Land Social Club and thereby murdered 87 people (check out
http://vikingphoenix.com/news/stn/1999/stn99005.htm for more details). Anyway, I don't recall anybody campaigning for permits to buy gasoline, registration of gasoline "arsenals," etc. Everybody knew that the gasoline didn't put itself in the bottle, carry itself to the Happy Land, stuff a rag in the bottle, open the door, light the rag and toss itself into the club. Well, guns have the same capacity to kill/murder human beings as the gasoline used in 1990 to murder 87 people - i.e. NONE. What disturbs me is that there are so many ignorant people out there that this kind of $hit spewed by HCI and the media actually is believed.
To me, the ultimate solution is education - take someone to the range who has no familiarity with guns, or is afraid of them, and teach them a thing or two. Write letters to the newspapers, etc. to show how they are ignorant (esp. about ballistic "fingerprinting") and never hesitate to make someone with whom you are discussing/arguing this issue look like the fool that they are.
End of rant.