Would You Do This to Prove a Point?

Yes, I would.

But in order to validate the theory, he'll need to perform a second demonstration in air.

That, I would not do.

I offer to pull the trigger for you

Maybe, after I had shot it a few times to verify the bullet wasn't going very fast where I would be standing.

I can just see the newscast the next morning, he was killed by a fluke occurrence of soft water generated by the new filter system which created tiny air bubbles and the use of a teflon coated bullet which was mixed in with the other ammo by mistake say experts...

If he had it set to rapid fire he may have gotten a very different result as each bullet cleared a progressively longer path through the water for the next one to follow.

Well, when I was a freshman in high school wood shop. I was using the electric hand planer and planing a 42" diameter American Elm block cut at a slight angle to make it oval by 6" thick, that I was making into a coffee table.

My instructor stopped me and took the hand planer away and began to scold me because I was operating the electric hand planing without first writing my safety rules on that hand tool, as he was pointing the hand planer at me. Saying that I could get hurt using this tool as he was pointing it at me, he lowered his arm to his side, he accidentally pressed the on button and proceeded to get his shop coat he was wearing wound up in the hand planer.

As a quick witted kid,.... Some would call it something else, I asked the instructor, I didn't quite catch that, could he show me the dangers again.

I passed that class that semester with a 'D-', the first boy that ever got a 'D-' in shop class.

..because no one will ever try this one yet. This should be the next bed thing. May be he should try a little harder next time, with this.

Hopefully it's not a supercavitating bullet...

http://www.guns.com/2012/08/28/pnw-arms-supercavitating-underwater-ammo/

Ha ha.. should have showed him the video just before he was going to pull the trigger....

A network engineer was practicing at the pistol range one day and wasn't hitting the target. He placed his finger over the muzzle and pulled the trigger, shooting his finger off. He proudly exclaimed, " the trouble must be at the other end".

Several seasons ago I saw an episode on Mythbusters where Adam and Jamie tried to verify that the practice of diving below the surface of water when being shot at would slow the bullet sufficiently as to case no harm.

I can't remember what rifle and round they were using, but they are both still alive.

If to prove a point, I would say NO, but if I was being shot at and had no other alternative, definitely YES.

I would think there would be a big difference with the rifle being shot from up above the water vs being shot underwater....as you can see from the video here, there is a big difference between type of weapon being used....

https://www.youtube.com/watch?v=Dihs9JcVt3E

AK47

https://www.youtube.com/watch?v=cp5gdUHFGIQ

more fun...

https://www.youtube.com/watch?v=r5y6EmERRKk

I beleive it was it was the history channel did a documentary on D-Day. On the German MG34 or MG 42 machine gun.

When the allies landed, particularly on Omaha Beach, that life and death amounted inches my being critically wound by this machine gun. Where they test fired it in a dunk tank and videoed the bullet through the water on the glass side of the dunk tank.

And by the difference between life and death by inches, I mean the water that is between you and the bullet.

It was quite interesting. And it's not like the movies portray it. And example in the movie 'Saving Private Ryan' on the landing they'd should soldiers struggling with their packs pulling them underwater, and a shell would rip through them when they are a couple of feet underwater, is unlikely.

And I say unlikely, because, they were there and I wasn't. It was a world of crap and survival was a premium.

Yes I recall watching that movie and they do show a soldier being hit while underwater and I remember thinking that this would not happen in real life, recalling the myth busters experiment. However its a movie and they need to make it dramatic.

oilcan13

Yes I recall seeing that episode. they used different calibers all the way up to and including .50 cal (a very large bullet).

oilcan13

The Mythbuster in the water (Adam) was also WELL outside the field of fire of the weapon the other one (Jamie) was firing into the water at the suspended Ballistics Jell target.

It seemed that the higher-velocity projectiles did not like the air-water transition at that speed and tended to 'schrapnel' themselves as they hit the water. the rounds never making it to the target.

Ammo is not all that is supercavitating.

More than one country has them now,including China.

Check out these torpedoes,and associated links:

Faster than sound,underwater? Scary!

https://en.wikipedia.org/wiki/VA-111_Shkval

Speed of sound in water ~ 3315 mph...

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe2.html

I think the link was referring to speed of sound through air.

There is nothing theoretically,however,to prevent the top speed of these torpedoes from exceeding that speed underwater.

Steering was the problem,but I think they solved that with high speed CPU's and steerable nose cone.

The actual top speed in test lab is classified,but rumored to be faster than sonar.

The technology has improved drastically in the last 40+ years, as has stealth diesel submarines.

Turn on your flashlight and listen; that is the sound of the new diesel subs,made in Germany and other countries.

They carry sufficient oxygen and Argon to run the diesels,and recycle the Argon by scrubbing it from the exhaust.

This enables significantly greater range than the older technology.

Not comparable to the range of a Nuclear sub,but much cheaper,which allows a small country to buy one.

The world is becoming more dangerous everyday.

Here is a link to go with my previous post:

http://foxtrotalpha.jalopnik.com/sweden-has-a-sub-thats-so-deadly-the-us-navy-hired-it-t-1649695984

..."This technology uses a submarine diesel engine which can be operated conventionally on the surface, but which can also be provided with oxidant, usually stored as liquid oxygen, when submerged. Since the metal of an engine will burn in pure oxygen, the oxygen is usually diluted with recycled exhaust gas. Argon replaces exhaust gas when the engine is started."...

https://en.wikipedia.org/wiki/Air-independent_propulsion

Here is another interesting link for a diesel that can run when sub is totally submerged.

https://www.quora.com/What-is-air-independent-propulsion-in-modern-submarines-that-is-being-built-by-Japan-for-Australia

How does this all equate to shooting fish in a barrel?

He's still a "dumb f*ck" for trying this. That is a H&K 416, most likely chambered in 9mm x 19 mm NATO, which the German Army prefers. It's not exactly the best performing round out there, with a lackluster muzzle velocity and low grain weight. If it had been a 5.56x45 NATO round it would most likely struck him.

Yeah, our own USN SEALS hump Heckler & Koch 416s, chambered in either 5.56 NATO or .308 NATO, because you can actually fire them underwater w/o fear of the weapon exploding in your hands, unlike many other infantry rifles and others.

Expect to see this moron's Obit in the paper someday if he's not careful.

Bullet dynamics very, very, simplified!

In order to make a comparison between behaviour in air and in water I assumed that in both media the drag coefficient is the same, I am aware that there will be differences but even with a simplified model the order of magnitude can be estimated.

The parameters are,

For the bullet: mass, the frontal area, initial velocity and the drag coefficient

For the fluid: the specific mass and its kinematic viscosity

The basic equation is: M*dw/dt=-F with the initial condition @t=0→w=w₀

The resistant force F depends on the bullet velocity especially in water. In a 1^st phase it is only dependent on the drag force

F_h=ξ*A_f*ρ*w²/2

In the second phase I presume that also a friction force on the lateral surface will add to the first F_f=η*A_L*k*w

The friction force is proportional to the velocity gradient at the lateral surface (within the boundary layer) which I approximate by the "k" coefficient.

If we consider only the 1^st phase the equation is:

M*dw/dt=- ξ*A_f*ρ*w²/2

We can write it as:

dw/w²=- ξ*A_f*ρ*dt/2

which can be integrated and gives, considering the initial condition, following equation for the velocity:

w/w_o=(1+t/T₁)^-1 with (1)

T₁=(w_o*ξ* A_f* ρ*/(2*M)

We can further integrate the velocity in order to obtain the displacement versus time :

S/(w₀*T₁)=ln(1+t/T₁)

Looking at equation (1) we can obtain a relationship between displacement and velocity in dimensionless parameters as

S/(w₀*T₁)=ln(w₀/w) (2)

The graph shows how velocity varies as function of distance.

A bullet is lethal in air a distance S_air and has at this distance the velocity w_L.

In water to still be lethal it should have same velocity w_L. If we assume that the initial velocity in both cases is the same then we can write that

S_air/T_1air= S_water/T_1water → S_water=S_air*T_1water/T_1air=S_air*1.3/999=0.0013013 * S_air

We know that a sniper can be effective at 1000m so that same bullet can have same effect at 1.3m.

If you place your self at for instance 3m there will be no harm.

In fact the non lethal distance is even shorter since this estimation did not take into consideration the second phase with the lateral surface friction. The dynamic viscosity of water is about 100 x bigger than same parameter of air which will reduce even more the lethal distance!

The pictures show the "tester" at distances around 3 m from the riffle whic is coherent with my simplified estimations!

I strongly suggest we use lawyers for the test.

And we have to do it in multiple tests to verify it... Scientifically..

Oh, there's a line starting to form as the marksman... whoa...., hold it...... wait till he gets in the water...