Hey All,
I found this on line… A chest protection plate of level IV body armor.
If I fashion that into a shield, putting it into a sturdy cloth “bag” with loops to hold it on my arm and run at an active shooter, chances are very low, and the shield takes a hit near the top of the surface…will the shield rotate back? Deflect the bullet at my head? break my arm? Bullet from an AR-15 style rifle.
Thanks!
Assuming it stops the round, you’ll only feel as much as the the shooter feels in recoil.
The one video right on that page makes it look like the bullet gets pretty deep into it. ISTM, that would make it unlikely to go up towards your face if it took a shot straight on. I would guess that the bullet would likely bounce straight back. But in any case, whatever the bullet does do, it’ll be done doing long before the entire shield has a chance to rotate at all.
Another thing to keep in mind, a slower round will probably ricochet off that much better, faster and at a more unpredictable angle. If it doesn’t break the surface, or only dents it, it’ll be allowed to fly off in another direction. If it gets into it, can really only go back out.
And like snfaulkner, it’ll can only push as hard as it pushed on the gun when it left. Considerably less actually since it loses speed as it travels. From a physics standpoint, I have no doubt that a person could hold it steady. IRL, maybe less so.
FWIW, they do have backpacks with integrated shields in them. You can just buy them online.
Not a bad idea, go for it. Nothing wrong with having extra protection. If you have time for a hobby you can always make some yourself. You could also make armor that wraps around your whole body, for a significantly less. You can buy 1/4 inch steel plates [welding or otherwise] at a hardware store and some ceramic tile (not bathroom tile), fiberglass tape (drywall tape works). Layer Metal>Ceramic>Metal and wrap it in 1/4 inch of taut fiberglass tape, tight and covering each section. You can fashion a carrier for it out of gardening aprons. Doing it this way has stopped a 5.56mm round at 100 yards on a mannequin. It’ll be quite heavy depending on what areas you cover, but affords protection on the cheap with access to 50 bucks at a hardware store. The only drawback is no innate curvature like the prefabricated stuff above, which does have some inherent benefits.
Is this not what you are referring to?
I understand that didn’t work out so well for Ned Kelly in Australia.
Better and cheaper at home, eh?
Thanks, I looked at those and they don’t seem rated for AR-15 style rifle bullets, more for handgun rounds.
Sooo… the materials used for armor are typically not standard stuff like steel and aluminum from the hardware store. They are designed purposefully in such a way, that when the round hits the front, that the back doesn’t blow out into shrapnel. Using 1/4" hot/cold/whatever steel would probably be a bad idea as it won’t absorb and deform as it needs too.
Here’s a handy table of handgun ballistics:
Bolding mine.
I’m beginning to worry about you.
Like being able to move.
The round has the length of the barrel to accelerate, but a shorter distance to decelerate when it strikes the shield, also other factors, such as mass, and flexibility and vibration. Not sure the ‘feel’ would be the same.
Good point.
Reaction force VS time duration (and area) is of the essence.
The momentum of the bullet is the same, or slightly smaller, than when it left the barrel. Force is the time rate of change of momentum. The bullet is moving slightly slower but has a much smaller distance to stop in against a shield compared to being fired from a rifle, even if both of the times are very short, meaning that the shield will need to change the bullet’s speed much more rapidly than the firearm did. Thus the magnitude of the force imparted by the bullet onto the shield (which is equal and opposite to the force the shield imparts on the bullet to stop it). If the bullet slows significantly and/or the shield is allowed to be penetrated more, the force needed would go down. That’s just the force on the shield though. If you’ve rigged it so that the shield is resistant to twisting from being struck off-center and give the shield some room to stop over instead of trying to maintain it still, then the force your body would need to impart would possibly be less. Of course, if they’re firing faster than your shield resets its position, that’s not much help.
You can always just buy an actual ballistic shield before you play Captain America. Even has a little window which would be lacking from your home made job.
This is what you seek (unless he happens to be shooting green-tip ammo).
Sexist. 
That is what I was looking for initially and I couldn’t find it. Thanks. Odd that the page claims level III protection when describing level IV protection stopping power.
I won’t pretend to know anything really about how they get rated; I just assumed a shield that could stop a 7.62 rifle round would work against an AR-15 (usually .223 or 5.56, I believe?)
Turns out I was wrong on the levels. IIIa is pistol(ish) rounds, III is rifle(ish) rounds and IV is armor piercing.