That is rated up to 7.62 x 51 mm NATO, considerably powerful than the 5.56 mm ammunition used in most AR-15 rifles.

Level III is good enough for protection against typical hunting ammunition.

III-A is NOT rated for rifle fire.

FYI that s standard police vest.

Go read more on it.

Here

http://www.bulletproofme.com/Ballistic_Protection_Levels.shtml

Type III plate will stop 5.56 NATO

Will realize that ceramic plate is hard to conceal

They will also knw they are mostly not available in the civilian market

They will also knw that whatever...gun bunnies.

Maybe we all shoud do the intelligent thing and buy chameleon armor, since a well armed society requires a well armored society.

The astute reader will realize some of us are talking of way you can get (in California armored clothes are stil legal, armored vests not so much), including these backpacks, will not stop a riffle round.

Of course the astute reader will know it s not bullet proof, buy bullet resistant. And te astute reader will realize the stupidity of this.

Nij widely available body armor is up to III-A.

A bit heavy for a kindergartener, no?

Every child in America needs to wear a kevlar-reinforced helmet along with full body armor - all day every day, and probably at night. Heck, every adult, too.

Because it's NOT FAIR to restrict gun ownership or punish irresponsible gun owners.

Exactly right.

of the utterly insane.

Not rated for rifle fire, and ceramic plate. The latter s quite heavy. Police trauma plates (worn in an insert on the chest by many cops) are ceramic plates as well.

And how proficient with the weapon would that teacher need to be to do it ?
would they need to be a marksman or expert for a potential required head shot?

Soft flexible armor made of kevar, zylon, or UHMWPE (commonly worn by police) are rated NIJ II, IIA, III, & IIIA. They really only stop shotguns and pistols. If you want to stop rifles you need to wear more of a SWAT or Army rig. Google NIJ ballistic ratings for comprehensive information.

The Army issues me level IV Ceramic front, back, and side/rib plates in a IIIA kevlar lined carrier. The kevlar will stop pistol and some flak/shrapnel, but the Plates are there to do 90% of the work. Without the heavy plates, the armor is pretty pointless to wear since insurgents use AKS. The plates alone are rated to stop multiple .30-06 AP (armor penetrating) hits @ point blank.

The plates are about 1" think and the kevlar and carrier add about another 3/8" of bulk. The vest weights about 45 pounds alone... another 10lbs or so if you put on all the extra kevlar shoulder, neck & groin extensions (almost nobody adds this extra stuff except EOD). Steel plates are thinner, but a bit heavier - I don't think anyone is issued those anymore. It's possible the bulletproof backpacks have a rifle plate in them in addition to a IIIA panel... but now you're asking a kid to carry 15 pound empty backpack. I doubt that's the case. My thinking is that they are only lined in soft armor. Novel idea, in my opinion.