how thick does steel have to be to become bulletproof?

Question

I know it depends a lot on the velocity and guage of the bullet being fired at it, but how think does steel have to be to become bulletproof?

Answer 1

it depends on lots of stuff...
The kind of steal....
The bullet being fired...
The material the bullet is made of...
The speed the bullet hits the steel at...

But generally you can penetrate about 1/2 " steal with either a .223 (5.56mm) AR-15 green tip, fired at <50yards.
Or a 7.62X39 Soviet round (AK-47)
Hope that helps



HOLY SHIP!!!... I just read what the guy above my answer wrote.. That is total BULL!!! A .50BMG wouldn't penetrate 6" of steel. That is crazy!!! 6" of steel is what they use in hi grade bank vaults... Do you think they would use that if you could penetrate it with a simple AK-47?... I don't think sooooo.
And how the heck can he say it will penetrate MORE steel then aluminum???? What a crock!
sheeesh

Answer 2

There are strict tests which are used to classify bullet resistance, and which specify the detailed characteristics of bullets that the material or object must be resistant to. For example, the United States National Institute of Justice standard 0104.04(http://www.nlectc.org/pdffiles/0101.04RevA.pdf) for bullet-resistant vests specifies that a Type II vest must not deform clay representing the wearer's body when hit by an 8.0 g (124 gr) 9 mm caliber round nosed full-metal jacket bullet travelling at up to 358 m/s (1175 ft/s); but a Type IIIA vest is needed for protection against the same bullet travelling at up to 427 m/s (1400 ft/s). In both cases, the vest is not required to protect against a second hit within 51 mm (2 inches) of the first.

Answer 3

First it depends on the Round being fired

However, using 7.62, i would guess around 4" of aluminum, or 3" of Titanium and around 6" of ballistics grade steel

Note to the USMC Dude:

1. A real marine would know that .50 BMG is 12.7mm not 7.62mm
2. Mythbusters penetrated the bottom of a scuba tank (3.5" Aluminum) with an M1 Garand (7.62)
3. .50 BMG is more than capable of penetrating 6" with a teflon tip, it is designed to do so..."Anti - Material Round" It can blow straight through the gearbox of a chopper....
4. These are rough estimates to be COMPLETELY Bullet proof.
5. .223 Rem is not caparable to a 7.62 or .50BMG for metal armor penetration

Answer 4

Not trying to sound like a tough guy, but about the only time I cry is due to death. I tend to become more pissed than upset over things. I guess I'm a very stereotypical male in that regard. Did Incubus of all people really just call someone else a sociopath and a psychopath?

Answer 5

There probably is no set answer. There are a lot of variables like the size of the projectile and whether or not it's 'armor piercing'. I've worked around tanks a lot and I know that armor plate is special steel. It's not the 'regular' stuff.