Energy Weapons VS Ballistic Weapons

[Falkus]

A heavy pistol, such as the Colt .45 or the Glock .40 will also knock you on your butt.

And by Newton's laws of physics, it should do the same thing to the man who pulled the trigger. Every action has an equal and opposite reaction.

 

[Ralts Bloodthorne]

And by Newton's laws of physics, it should do the same thing to the man who pulled the trigger. Every action has an equal and opposite reaction.

It's called recoil, which is why there are stocks, and why the blowback mechanism and recoil springs exist in rifle, as well as why the pistol grib is shaped in such a way and the blowback design is the way it is. Remember, older pistols (which delivered far less kinetic energy) would cause major recoil, enough to throw one's arm up.

Other reasons while a lot of people think that Newton's expalins it don't realize that most heavy weapons, from assault rifles to sniper rifles to heavy machine guns, have recoil springs to help dampen the recoil force and bleed it off. I do know that a bad recoil spring in an M-16A1 will give the firer a broken shoulder.

Plus, if you just say: "Newton's Third Law" you aren't taking into account that a hard punch from a trained fighter will actually lift you up and toss you back, or knock you flat on your butt, and a punch delivers a LOT less kinetic energy than a pistol round. Why didn't the fighter end up on his back?

The More You Know...

Now, since that was half sarcastic, I will admit, it started making me curious. So I went and looked up various medical and field reports...

When I was hit, it knocked me off the back of the truck. It also hit with enough force to pop one of my ribs.

Here's the weird thing, while Mythbuster's claims it was a myth, and the guy who created the Second Chance vest shot himself in the chest while on one foot, there has to be some reason that some people are "tossed back" about a foot or two (No, not flying through the air for 50 feet) or thrown to the side (it's hard to explain) while other people just jerk and drop.

Some of it might be muscle spasm/nerve shock, final muscle spasms, etc.

Having not seen the Mythbuster's in question, and only going off of first person observations, I'm still convinced that there is signifigant knockback (IE: less than 2 foot, although it seems like your airborne for a LOOOONG time if your the one shot) in the case of armored vests.

Huh....

The More I Know...

 

[Peterson]

and the guy who created the Second Chance vest shot himself in the chest while on one foot

Don't quote me on this, but I believe I saw an article in the Detroit Times about this guy. Seems he actually made faulty vests, and it got two (and possibly more) police officers killed.

If I remember right (from my quick skim of the partial article), his company - Second Chance - is located in Central Lake, Michigan (which, off-topic, is where I went to summer camp and learned to shoot a rifle.).

Anyway, just wanted to bring that to anyone's attention that has ever used, uses, or plans on using a Second Chance vest. A simple Google search should find most of the relevant informaiton.

The more you know....and all that.

Peterson

 

[Corwyn_kop]

Well, this all got me thinking and poking around on the good ole 'net. The only study I could find on this topic specifically (mind you Im at work so my research time and options are limited) was by the International Journal of Legal Medicine...(sounds impressive doesn't it? ) All I found was the brief, which did not go into the methodology used, but they claim that the impact of small arms isnt sufficient to knock someone back.

Im actually thinking it might be worth asking some of the state troopers and prison guards that have participated in fireing squads what their experience was but it could be considered in poor taste.

It also occured to me that one factor that hasnt been considered is the reaction of the body to being shot. It seems with such a traumatic impact, their is a high likelihood of a physical reaction along the lines of a flinch or knee-jerk of epic proportions.

Im no doctor, nor alas do I play one on TV but thats my attempt to bring various personal experience cited here and what appear to be current scientific thought in line with each other.

Corwyn


P.S. If any of you should decide to experiment on this topic, I do NOT want to hear about it

 

[Armistice]

Mythbusters debunked the Hollywood version of knockback, that is all I was referring to. As to the physics/biology, since anecdotal evidence from people being shot with the same types of ammo differ greatly (some report falling backwards, others hardly realizing it, others drop straight down), I think the most likely cause for knockdown has to do with the shock to the system rather than the physics involved.

Good armour should result in the just kicked by a mule feeling (depending on the type of round absorbed) as that means the force of the bullet has been properly distributed over the armour's area rather than being used to penetrate the fragile body impacted.

Energy weapons as invisioned by sci-fi are essentially magical in nature. There may be some specific uses of directed energy (i.e targeting, blinding of sensors, cutting) that work efficiently. For general and even specific mayhem, however, kinetic (energy) weapons will always be cheaper to produce and so will deliver more bang for your buck.

 

[Captain Tagon]

That's one of the reasons I like the Schlock Mercenary world. Plasma cannons and gauss guns side-by-side.

I especially like the cee-sabots. Remind me of the heavy cannon from the Berserker books.

Too true. If I was going to write up my own sci-fi universe it'd be somewhere between HALO and Schlock Mercenary.

 

[Nadaka]

A rifle, particularly an assault rifle (yeah, a combat weapon) will knock you FLAT on the ground, even if your vest stops it. It will also break ribs and leave a really nice purple bruise for everyone to admire.

A heavy pistol, such as the Colt .45 or the Glock .40 will also knock you on your butt.

Honestly, I'd have to wonder if the guys from Mythbusters were using cold loaded ammunition, assault rifles, the rest? Or did they use a .22 or a .38 snub nosed revolver?

false. THe kinetic energy transfer is largely irrellevant. I can prove that kinetic energy transfer doesnt mean squat with simple physics. You get knocked down by the pain and shock of being shot, likely ampified by reflexive muscle spasms.

Lets model a simple collision between 2 objects

M1 = mass of target (assumed 80kg for an adult male)
M2 = mass of bullet
V1 = velocity of target
V2 = velocity of bullet

M1 * V1 = M2 * V2
solve for V1
V1 = M2 * V2 / M1

9mm parabellum: m2 = 7.5g, v2 = 390 m/s.
assumed average human weight(m1) = 80kg, velocity(v1) = 0.0365625 m/s.
Thats ~1.4 inches / second.

7.62mm NATO: m2 = 9.33g, v2 = 838 m/s.
assumed average human weight(m1) = 80kg, velocity(v1) = 0.09773175 m/s.
Thats ~3.8 inches / second.

.50 BMG: m2 = 42.9, v2 = 888 m/s.
assumed average human weight(m1) = 80kg, velocity(v1) = 0.47619 m/s.
Thats ~18.4 inches / second.

So in conclusion, normal personal firearms are not going to knock one on thier ass because of the impulse of collision. An Anti-material round like the .50 BMG can, but even a full powered round from a battle rifle isnt going to knock one head over heals. If it isnt the impulse that makes you fall down, it is most likely the "damage" that makes you fall down.

 

[hobgoblin]

hmm, blue planet still use slug trowers. however, they are fueld by a binary propellant (two gasses that by themselfs dont do much but when mixed go boom), use a electric trigger (spark, not hammer on cap) and the slug itself is a kind of very dense grown plastic.

only place they use something diffrent i under water, and there they use a kind of sonic laser, or saser as they call it. reason is that soundwaves travel much better under water then bullet (alltho they have some more aerodynamic bullets that get a bit more range under water then the normal type, but loose some of the bite).

makes sense in a way.

only place i can see a real use for energy weapons is boarding actions in zero gravity...

 

[C. Baize]

Didn't they also prove that bumblebees can't fly with physics, too?

Mathematical formulas are neat and look great on paper, but they don't ALWAYS transfer to real life circumstances.

 

[danzig138]

Didn't they also prove that bumblebees can't fly with physics, too?

Yeah.
In the 30s.
With faulty thinking.
It's not true anymore.

Just because one guy got knocked on his butt doesn't mean everyone does. Anecdotal is fun that way.

I don't mind a knock-down mechanic myself. A game we used to play had one, and it was always fun when a shot would put a bad guy down for a round or two.

Not so much when it happened to us, but hey, goose, gander, all that.