fifty caliber near miss, dangerous?

[TommyGunn]

Thou art all fools.  Don't thee know that Luke Skywalker destroyed the Death Star with a .50 caliber BMG?  One and done.  That is all.

"Placement is everything."

[just Warren]

Thou art all fools.  Don't thee know that Luke Skywalker destroyed the Death Star with a .50 caliber BMG?  One and done.  That is all.

I thought that was a protein torpedo.

[freakazoid]

The sun's corona might be "3.5 million degrees", however, assuming you were shielded from direct exposure from the photosphere, you'd freeze-dry from boiling/evaporative cooling because while it's "3.5 million degrees" it's almost hard vacuum as compared to terrestrial conditions, and it's ability to heat your body through conduction or radiation is almost nill.

What?

[Regolith]

What?

Vacuum can't conduct heat worth *expletive deleted*it, so if you're adequately shielded from the direct radiation of the sun, you'd be experience absolutely no heating from it, regardless of how close you were (though at some point you're going to run out of materials that can withstand the temperature and radiation enough to adequately shield you...)

Think of it like this: say there's an object radiating heat. Doesn't matter how much, but let's say it's enough to instantly vaporize you. You're standing in front of it with a shield that can resist the temperature and is just big enough for your body. In atmosphere, you'd be dead, because the energy from the radiating object would heat up all the air molecules next to it, and then those air molecules would heat up the air molecules next to them, and so on and so forth, with each air molecule transferring heat on down the line until the heat transfer has wrapped around your shield and turned you into ash.

In a vacuum, there are no molecules in the air that can transfer heat, so the only way that heat can affect you is if you're being directly radiated by it. If there's something in the way - like a shield that can withstand the radiation - you can't be directly radiated, and hence experience no heating.

[birdman]

Newton's Third Law of Motion. Unless my physics is mistaken, every action equal and opposite reaction. The amount of force hitting the person downrange is equal to the amount of force hitting the shoulder of the person firing, minus inefficiencies. For the Barrett, you do have recoil springs to help, so think bolt action .50 BMG to simplify the mental math. It stings a bit, but the shockwave traveling the body of the shooter is not lethal.

The projectiles are lethal because they concentrate all the force into a small area (less mass) and they have a small frontal cross-section. A bullet is very small, compared mass of a rifle.

So, to simulate the shockwave impact of a .50 BMG, put your hand or finger against a solid backrest, place a bolt action rifle on a near frictionless recoil platform against it, and pull the trigger. That is the MOST "shockwave" damage that will be caused. The downrange equivalent will be less, in terms of force and thus shockwave. It will be more concentrated, which is the entire point.

Kinda, but not quite.
At any instant, force is conserved.
Over time, momentum is conserved.
However, the time of interaction is different.
When firing, say a bolt action, the momentum of the bullet is equal to the impulse given to it--the integral of force over time (the time in this case being the time from breech to muzzle).
Say the bull the then immediately hits a soft, human thickness target made out of....reinforced metal and comes to a compete stop inside the target.

While the impulse on the target can be no more than the impulse on the rifle, the force can be much, much, higher.
To whit:
The peak pressure in a typical firearm is between 40-60,000psi, so let's call it 44-45 to make the conversion to metric easier.  ~45,000psi is approx 300MPa.
Now, let's say the bullet has a drag coefficient of 1 (again to make the math easier) and is traveling at 1000m/s (starting to see a trend?).  When it encounters the reinforced meat target (density 1000kg/m3) the peak drag force per unit frontal area it experiences is 0.5 * Cd*density*velocity^2, or in this case, 250MPa
(Drag force of 1 as the bullet is actually subsonic in meat, even though its supersonic in air)
In that case, the peak force on the target is less than the peak force on the breech.  However, that assumes there is no contribution other than an air analogous drag force, which actually depends what it hits.  Meat...yeah, the force is likely less than the firing.  Bone? Not so much.
If the target material can't flow out of the way ahead of the projectile, or if the structural strength starts coming into play then it becomes much, much higher.  If the bullet hits an immovable object that doesn't deform, and only the bullet does, the peak force can be EXTREMELY high--think about it, the force in the firing gun accelerated the bullet to its velocity in the length if the barrel, but the target decelerates it in the length of the bullet.
Assuming constant acceleration in both cases, you have distance = 1/2*v^2/a and if the length of the bullet is 1/20th the length of the barrel, you have 20x the peak force.

[RoadKingLarry]

 
It's all geek to me.

[RevDisk]

Kinda, but not quite.
At any instant, force is conserved.
Over time, momentum is conserved.
However, the time of interaction is different.
When firing, say a bolt action, the momentum of the bullet is equal to the impulse given to it--the integral of force over time (the time in this case being the time from breech to muzzle).
Say the bull the then immediately hits a soft, human thickness target made out of....reinforced metal and comes to a compete stop inside the target.

While the impulse on the target can be no more than the impulse on the rifle, the force can be much, much, higher.
To whit:
The peak pressure in a typical firearm is between 40-60,000psi, so let's call it 44-45 to make the conversion to metric easier.  ~45,000psi is approx 300MPa.
Now, let's say the bullet has a drag coefficient of 1 (again to make the math easier) and is traveling at 1000m/s (starting to see a trend?).  When it encounters the reinforced meat target (density 1000kg/m3) the peak drag force per unit frontal area it experiences is 0.5 * Cd*density*velocity^2, or in this case, 250MPa
(Drag force of 1 as the bullet is actually subsonic in meat, even though its supersonic in air)
In that case, the peak force on the target is less than the peak force on the breech.  However, that assumes there is no contribution other than an air analogous drag force, which actually depends what it hits.  Meat...yeah, the force is likely less than the firing.  Bone? Not so much.
If the target material can't flow out of the way ahead of the projectile, or if the structural strength starts coming into play then it becomes much, much higher.  If the bullet hits an immovable object that doesn't deform, and only the bullet does, the peak force can be EXTREMELY high--think about it, the force in the firing gun accelerated the bullet to its velocity in the length if the barrel, but the target decelerates it in the length of the bullet.
Assuming constant acceleration in both cases, you have distance = 1/2*v^2/a and if the length of the bullet is 1/20th the length of the barrel, you have 20x the peak force.

I should have specified total force vs peak force. 

I'm obviously not at your level of physics (Well, no excrement, there), but AFAIK, you have both being theoretically equal forces and then add in the real world. Inefficiencies such as drag. The total transfer should be equal to the recoil (minus losses), just vary in duration and area, with both being very important. Recoil is much longer than say, the amount of time it generally takes a bullet to get through a human body. Or even hitting a plate in body armor. The reason it hurts so much is that the force is delivered quickly. It's spread out over a larger area, but the durable is very short, thus high deceleration.

Density changes the duration, yes? Which greatly changes the peak force, but not total force?

[birdman]

I should have specified total force vs peak force. 

I'm obviously not at your level of physics (Well, no excrement, there), but AFAIK, you have both being theoretically equal forces and then add in the real world. Inefficiencies such as drag. The total transfer should be equal to the recoil (minus losses), just vary in duration and area, with both being very important. Recoil is much longer than say, the amount of time it generally takes a bullet to get through a human body. Or even hitting a plate in body armor. The reason it hurts so much is that the force is delivered quickly. It's spread out over a larger area, but the durable is very short, thus high deceleration.

Density changes the duration, yes? Which greatly changes the peak force, but not total force?

There is no such thing as total force.  There can be either average force, or impulse, which is the time-integral of force.
I think you mean impulse, which is the change in momentum...which I addressed :)