Sharpshooters, Reach out and touch someone Options

[KarmaInferno]

... or "high angle" just means high compared to normal shooting but not above 45 degrees.

Pretty much this.

Also, I think the intent was to get an Afghani sniper to duck or otherwise stop shooting at him, not with any real hope of actually killing the guy, but he scored a lucky hit and took out the sniper's rifle.





-k

[CanRay]

Still prefer the tankers solution to snipers.

Then again, I also like explosions...

[MikeKozar]

So let's see.

Either the soldier actually fired his weapon in a wholly ineffective way against his better knowledge.

Or the soldier fired the weapon effectively, and either KarmaInferno heard the story wrong, or the guy who told him the story told it wrong, or KI told it wrong, or "high angle" just means high compared to normal shooting but not above 45 degrees.

That's the third post you've made which attacks KarmaInferno for his improbable Soviet anecdote. Just curious - were you looking for a retraction, an apology, or both?

I did some Googling, and it looks like machine guns have historically been used in indirect fire mode, particularly when ammo is plentiful and area denial is an objective. One example given is on the Western Front in WWI, where machine guns were used to pepper the area behind the trenches to make resupply difficult. Source: http://www.ww2f.com/small-arms-edged-weapo...-effective.html

The trick seems to be that historically, it is used as suppression fire, and enemy casualties were not the main objective. There seems to be some question as to how lethal a lucky hit from an indirect barrage of machinegun fire would be, but if you're just trying to harass enemy movement and logistics, it could be of significant psychological value.

As far as sniping someone at close range with an assault rifle, by shooting nearly straight up? Seems like more trouble then it's worth. After all, situations like that are what grenades are for.

[Blitz66]

I don't know how true it is, but my high school physics teacher said that a bullet fired into the air would come down with almost exactly the same force it had when it left the barrel, because air resistance on it is negligible and gravity would act equally to slow it down and then to speed it back up, over the same distance. So the force shouldn't really be an issue.

The real problem is aiming. Even if you had a formula on hand to calculate the precise angle you need, the best it could do, in my opinion, would put it in the center of a fairly wide circle that the bullet will fall into. Every tiny irregularity affecting its flight path would have the full length of the parabola to alter the trajectory. So yeah, you could put lead into the air for indirect fire, but unless you're firing into an enemy mosh pit, you're probably not going to hit anything worth hitting, even with the perfect angle provided to you. Cover fire is the only really effective way to use it.

Unless you happen to have an enemy mosh pit handy. In that case, have fun.

[KarmaInferno]

As I said a few posts ago, "high angle" meant "higher than is normal for direct fire". Apologies if I was unclear.

Mythbusters did testing on actual high angle gunfire, though, and concluded that if the round was being fired at a steep enough angle to actually have gravity be able to significantly bleed off the force, then yes, the bullet would be more or less non-lethal when it finally came back down. This happened mostly at very high to vertical angles - the bullet would lose momentum and slow down, stop, and gravity would pull it back down. Really, it would be no different than someone up at the apex of the bullet's flight just dropping a bullet. At worst maybe you'd get a bruise if it hit you.

However, at lower angles where the bullet can mostly maintain it's forward velocity throughout it's arc, the round was probably still very much lethal if it actually hit someone. There's been actually quite few incidents of accidental shootings this way - one medical center in LA reported in a ten year span in the 80s to the 90s over a hundred cases of folks getting hit by bullets fired into the air around the holidays. About a third were killed in the accidents.

I don't know how true it is, but my high school physics teacher said that a bullet fired into the air would come down with almost exactly the same force it had when it left the barrel, because air resistance on it is negligible and gravity would act equally to slow it down and then to speed it back up, over the same distance. So the force shouldn't really be an issue.

It's not true. The amount of force exerted by the powder charge of a bullet being fired is MUCH greater than anything gravity can impart to the same bullet. The only reason gravity can stop a vertically fired bullet is because gravity exerts a continuous downwards force, whereas the bullet's upward energy is supplied all at once from the powder charge.

Also, the story I related, if it is indeed true, had the soldier using multiple rounds, adjusting his angle as his spotter told him how far he was off target. Which is what "walking fire' means.



-k

[CanRay]

Math is hard. I'm going to go make cookies for the boys. Tee hee.

[Smokeskin]

That's the third post you've made which attacks KarmaInferno for his improbable Soviet anecdote. Just curious - were you looking for a retraction, an apology, or both?

I don't think there's anything wrong with KarmaInferno's story. Walking fire in with a spotter isn't uncommon with for example tri-pod mounted machine guns. The technique can be used without a mount, but it is very difficult because you're aiming at a spot in the air and have to correct from that - which is why it is a good story that a guy does it with an AK-47.

It was only the interpretation that he was aiming at an angle above 45 degrees I was objecting to. I wasn't looking for anything from KarmaInferno, except maybe the confirmation that the story wasn't about aiming above 45 degrees, which he gave. He and I are seem to be in perfect agreement on it.

I did some Googling, and it looks like machine guns have historically been used in indirect fire mode, particularly when ammo is plentiful and area denial is an objective. One example given is on the Western Front in WWI, where machine guns were used to pepper the area behind the trenches to make resupply difficult. Source: http://www.ww2f.com/small-arms-edged-weapo...-effective.html

Indirect fire doesn't have to be plunging though. If the terrain is right, you can place yourself so a small hill covers your position, but the bullets can arc over it and hit the target without plunging. Much more deadly and much more precise. If you want to drop bullets down into trenches, you'll need plunging fire by firing closer to vertical. It needs a mount made for it I would think, or digging a hole for a mount so it is steady and pointing upwards though, as most mounts won't elevate that high. Without elevation markers or some other way of aiming, you'd be very hard pressed to get rounds falling into the area for any type of indirect fire.

[Traul]

It's not true. The amount of force exerted by the powder charge of a bullet being fired is MUCH greater than anything gravity can impart to the same bullet. The only reason gravity can stop a vertically fired bullet is because gravity exerts a continuous downwards force, whereas the bullet's upward energy is supplied all at once from the powder charge.

You missed the point. The gravity magnitude does not matter. Gravity slows down the bullet on the way up, then it accelerates it on the way down, and the two exactly cancel each other. If the target is at the same altitude as the shooter, the bullet reaches him at muzzle speed. What if you take the same shot on Jupiter? Muzzle speed. And on the moon? Muzzle speed too.

The only thing that really slows down the bullet is air friction. Indirect fire is less lethal than direct because the trajectory is longer so the bullet suffers from more friction. Gravity has nothing to do with that.

[Smokeskin]

However, at lower angles where the bullet can mostly maintain it's forward velocity throughout it's arc, the round was probably still very much lethal if it actually hit someone. There's been actually quite few incidents of accidental shootings this way - one medical center in LA reported in a ten year span in the 80s to the 90s over a hundred cases of folks getting hit by bullets fired into the air around the holidays. About a third were killed in the accidents.

Under normal firing, the drag forces on the bullet is strong enough to overcome the gyroscopic effect and keep it pointing nose forward. If you fire it close to straight up, at the top of the arc the trajectory changes direction quickly while the air speed is so low the drag can't overcome the gyroscopic force. So the bullet is now travelling somewhere between backwards and sidewards through the air, and drag destabilizes it - the axis of spin remains largely unchanged compared to the ground, but the bullets orientation changes so it is no longer spinning nose-to-tail (sort of like a spinning top as it falls). I'm pretty sure this is what mythbusters saw, the projectiles were hitting the ground sideways, but they misinterpreted why - I believe there was still spin along a vertical axis, but the bullet had turned so it's length axis was describing a cone.

Falling that way, the bullet has high air resistance and won't hit hard, and getting killed by that would be very unlucky.

A bullet that can keep its nose oriented in the direction of flight however, that will hit very hard, especially a rifle bullet with a high ballistic coefficient - it is very aerodynamic and has a high sectional density, so its terminal velocity will be significant.

[Smokeskin]

I don't know how true it is, but my high school physics teacher said that a bullet fired into the air would come down with almost exactly the same force it had when it left the barrel, because air resistance on it is negligible and gravity would act equally to slow it down and then to speed it back up, over the same distance. So the force shouldn't really be an issue.

Air resistance is very significant. The round I use for hunting loses 32% of its velocity in just 300 meters of flight. Even a .408 Cheytac round loses over 10% of its velocity over 300 meters.

Because of this, the bullet won't go nearly as high as would be needed to accelerate it back up to muzzle speed even if it was in a vacuum on the way down, and air resistance will slow it falling down too. And is I commented above, if fired too straight up, it won't come down nose first, making it even worse.

[KarmaInferno]

You missed the point. The gravity magnitude does not matter. Gravity slows down the bullet on the way up, then it accelerates it on the way down, and the two exactly cancel each other. If the target is at the same altitude as the shooter, the bullet reaches him at muzzle speed. What if you take the same shot on Jupiter? Muzzle speed. And on the moon? Muzzle speed too.

The only thing that really slows down the bullet is air friction.

Incorrect.

A) Escape Velocity is a little above 11000 meters a second.

An AK can generate barely 715 meters a second. Even on a planet with no atmosphere, gravity would still eventually overcome the bullet's momentum and drag it back. Air friction does have an effect as well, but it's not the only effect in play.

B) There is a maximum downward force gravity can impart to a bullet.

You know that air friction you mentioned? Applies against gravity too. Only since the overall pull of gravity at any given point is much lower, you reach the point where the downward pull of gravity is equal to the resistive effect of air friction MUCH faster. At this point gravity cannot accelerate the bullet any further. This is known as terminal velocity.

The gun overcomes the air friction on the upwards leg of travel by sheer massive force.

Indirect fire is less lethal than direct because the trajectory is longer so the bullet suffers from more friction. Gravity has nothing to do with that.

This part is somewhat true. However, if the AK is generating 1500 foot pounds of force to a target, and 600 foot pounds is the lethal amount, reducing the bullet's striking force to 1200 FP or 1000 FP is still "lethal", even if it is technically "less lethal".





-k

[MikeKozar]

Indirect fire doesn't have to be plunging though. If the terrain is right, you can place yourself so a small hill covers your position, but the bullets can arc over it and hit the target without plunging. Much more deadly and much more precise. If you want to drop bullets down into trenches, you'll need plunging fire by firing closer to vertical. It needs a mount made for it I would think, or digging a hole for a mount so it is steady and pointing upwards though, as most mounts won't elevate that high. Without elevation markers or some other way of aiming, you'd be very hard pressed to get rounds falling into the area for any type of indirect fire.

No, no, of course not. Per the linked webpage, the indirect fire wasn't going into the trenches, but rather being spread around the field behind the trenchworks. That is to say, if you were trying to run supplies in from the next town, you would need to worry about stray bullets until you got into the trenches, and that was deliberate. I suspect that this only works if the elevation to drop behind is reasonably low and the distance is reasonably far, but I would probably consider letting players in my game use a heavy weapon for suppression fire over a wider range if the situation was right and the enemy had appropriate odds of a miss.

[Mardrax]

Incorrect.

I think he was just talking about the bullet impacting the ground at the same speed it left the muzzle, if it'd be fired straight up. This would be mostly correct when ignoring air resistance, which a high school physics teacher would often be happy to do. (mostly, because I'm assuming the muzzle isn't at ground level)
Sadly, you can't.

While a bullet is generally shaped for optimal aerodynamics, and fired from a rifled barrel to keep it on a course that makes maximum use of that, air resistance is still considerable on an object with that kind of speed. When it comes back down, it likely loses the stabilising spin, starts tumbling and rolling, and aerodynamics go to hell, increasing air resistance manifold.

This not only makes impact speed smaller, but very likely also makes impact area larger, since it's unlikely the bullet strikes point-down. This distributes the force over a much larger area, which decreases trauma, and greatly decreases chances of penetration.

[Aku]

I think he was just talking about the bullet impacting the ground at the same speed it left the muzzle, if it'd be fired straight up. This would be mostly correct when ignoring air resistance, which a high school physics teacher would often be happy to do. (mostly, because I'm assuming the muzzle isn't at ground level)
Sadly, you can't.

While a bullet is generally shaped for optimal aerodynamics, and fired from a rifled barrel to keep it on a course that makes maximum use of that, air resistance is still considerable on an object with that kind of speed. When it comes back down, it likely loses the stabilising spin, starts tumbling and rolling, and aerodynamics go to hell, increasing air resistance manifold.

This not only makes impact speed smaller, but very likely also makes impact area larger, since it's unlikely the bullet strikes point-down. This distributes the force over a much larger area, which decreases trauma, and greatly decreases chances of penetration.

This was found in the aforementioned mythbusters episode as well, iirc. instead of getting a "hole",shaped like a bullet, the ground had an oblong indention, indicating that the bullet had turned sideways and was tumbling on its return trip.

[Smokeskin]

This was found in the aforementioned mythbusters episode as well, iirc. instead of getting a "hole",shaped like a bullet, the ground had an oblong indention, indicating that the bullet had turned sideways and was tumbling on its return trip.

This is most likely not the case though. The axis of spin is still vertical, but the bullet just isn't pointing nose up. External ballistics studies have shown this, and it is very difficult to imagine the force that would eliminate the bullet's spin.

[Aku]

Bullets fired into the air maintain their lethal capability when they eventually fall back down.

busted / plausible / confirmed

In the case of a bullet fired at a precisely vertical angle (something extremely difficult for a human being to duplicate), the bullet would tumble, lose its spin, and fall at a much slower speed due to terminal velocity and is therefore rendered less than lethal on impact. However, if a bullet is fired upward at a non-vertical angle (a far more probable possibility), it will maintain its spin and will reach a high enough speed to be lethal on impact. Because of this potentiality, firing a gun into the air is illegal in most states, and even in the states that it is legal, it is not recommended by the police. Also the MythBusters were able to identify two people who had been injured by falling bullets, one of them fatally injured. To date, this is the only myth to receive all three ratings at the same time.

[Mardrax]

Shame Mythbusters is far from a reliable source. They've messed things up on more than one occassion.

[DWC]

This is most likely not the case though. The axis of spin is still vertical, but the bullet just isn't pointing nose up. External ballistics studies have shown this, and it is very difficult to imagine the force that would eliminate the bullet's spin.

The same air resistance that saps the round's forward (or vertical in this case) velocity is going to degrade the angular momentum, reducing the spin. The forces are easy to imagine from a fluid mechanics perspective.

[CanRay]

There's only one solution to this: TO THE FIRING RANGE!!!

*Runs off and comes back sheepishly* Um... You folks in the States can do that...

[Tymeaus Jalynsfe...]

There's only one solution to this: TO THE FIRING RANGE!!!

*Runs off and comes back sheepishly* Um... You folks in the States can do that...

Heh... No Range, eh CanRay? Poor Canadian... (IMG:style_emoticons/default/smile.gif)

[CanRay]

No range, no firearm, not wanting to deal with all the watch lists I'd be put on for purchasing a legal one with today's laws...

Damned 'Tories, I agree with them on one thing, and it's the one they bail out on.

[Tymeaus Jalynsfe...]

No range, no firearm, not wanting to deal with all the watch lists I'd be put on for purchasing a legal one with today's laws...

Damned 'Tories, I agree with them on one thing, and it's the one they bail out on.

(IMG:style_emoticons/default/frown.gif)

[CanRay]

Don't even get me started on the firearms registry and the travesty that's been.

Back to shooting people in the face for money at one mile, please, before I get started.

[Tymeaus Jalynsfe...]

Don't even get me started on the firearms registry and the travesty that's been.

Back to shooting people in the face for money at one mile, please, before I get started.

How about that BARRETT? Hell of a Rifle...

[Stahlseele]

And it's kinda legally obtainable right?