why handgun bullet is round nosed?

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and starts firing, you shoot back, but, the round 9mm can't penetrate as well as 5.7, may skid off all kinds of angled surface, don't you wish your bullet has pointy nose and penetrate better?
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Oh, sure. 'Course I'd want it to be a lot better than a 30 gr. bullet, too!

Remember, there's no reason to believe that a 5.7 would penetrate ANYTHING except a kevlar vest better than 9mm or a .40 or whatever other common sidearm cartridge would. AND THAT'S ONLY WITH AP AMMO YOU CAN'T GET.

Poking little tiny holes in kevlar vests is what they do well. Burning though a 28 gauge sheet metal fridge door, or a 1/2" drywall wall or a spruce 2x4? A 9mm will do just fine. In fact, some people say TOO fine a job, and they'll take a 5.56mm carbine round as it is likely to penetrate less than the heavier 9mm slug.
 
wouldn't pointed nose make it more areodynamic
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only if it were supersonic.... which many handgun loadings are not.

Look at the nose of a 747 and compare it to the B1 bomber. Then guess which one flies faster than sound and which one doesn't.

Both are designed for optimum aerodynamics for their flight conditions.
 
i really don't get this, the BG breaks your door, you hear it, you grab your 9mm, he sees you, life and death, he hides behind door/table/shelf/fridge/... and starts firing, you shoot back, but, the round 9mm can't penetrate as well as 5.7, may skid off all kinds of angled surface, don't you wish your bullet has pointy nose and penetrate better?
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Did you read where I posted just above the one you replied to that armor and barriers are not the same thing and are not defeated by the same mechanisms?

Couches, tables, whatever, are best beaten by a higher momentum projectile (not the 5.7) and if momentum is close enough, a narrower projectile will probably do better than a roughly equal but wider bullet.

www.theboxotruth.com
 
just did some calculation about kinetic energy:

kinetic energy=1/2*m*velocity^2 (ignore unit, just for comparsion)

9mm: 1/2*115*1155^2=76,700,000 (Winchester FMJ)
.45acp: 1/2*230*835^2=80,180,000 (Remington FMJ)
5.7mm: 1/2*31*2130^2=70,300,000 (SS190)

not much difference i'd say

kinetic energy is the energy that's used to do the destruction
 
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Do it again for momentum.

And who uses a 115 grain at 1155 for defense in 9mm anyway?

Also take bullet construction and what's actually being shot into account.

How does light wood and fabric affect a 9mm or .45 bullet?

Not much, right?

How does it affect a lightly constructed, light for caliber 30 grain varmint-type .224 bullet?

A little more dramatically, right?

There's way more going on than just energy levels.
 
kinetic energy is the energy that's used to do the destruction
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KE is only part of it.
http://www.thehighroad.org/showpost.php?p=8401076&postcount=26

Also, here's the correct formula for KE of a bullet - http://www.thehighroad.org/showpost.php?p=8400819&postcount=5

Using your example weights and velocities that comes out to 312 ft lbs for 5.7x28, 340 ft lbs for 9mm, and 356 ft lbs for 45 ACP. None of those are anywhere close to having enough energy for hydrostatic shock to be a wounding mechanism. Even the mighty 10mm pushing 180 gr slugs at 1200 fps and creating 700 ft lbs of energy is not enough to wound by hydrostatic shock. Which brings us back to the handgun wounding mechanism of what round can poke the biggest hole the deepest. 5.7x28 barely penetrates 10 inches of calibrated ordnance gelatin, and has minimal expansion. In other words, 5.7x28 has very poor terminal ballistics.
 
kinetic energy is the energy that's used to do the destruction
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I don't think anyone really believes that KE is the key to destructive capacity/lethality any more.

So, once more, we're back to penetration above every other factor (which no one believes IS the only important factor) and we've illustrated why, with the ammo you can buy, the penetration is going to be lousy, too.

Shoot whatever cartridge you want to, but this discussion is getting circular.
 
ugaarguy said:
KE is only part of it.
http://www.thehighroad.org/showpost.php?p=8401076&postcount=26

Also, here's the correct formula for KE of a bullet - http://www.thehighroad.org/showpost.php?p=8400819&postcount=5
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i know how to calculate kinetic energy (i have advance degree in physics btw, ph.d actually), your formular is just with unit conversion included, also kinetic energy of the bullet is ALL of it, all of the energy there is to do the destruction, by physics law of conservation of energy, it will not be created out of thin air unfortunately. there's simply no other forms of energy the bullet carries, the heat is tiny amount which can be ignored, there's no powder inside bullet to burn so there's no chemical energy to use. the kinetic energy is all the energy to do the damage.

comparing to rifle round
5.56mm: 1/2*55*3200^2=281,600,000 (m193)

is about 4 times the kinetic energy compared to handgun bullets, while different handgun bullets carry about the same amount of kinetic energy

in case you are wondering, the .45acp should have more powder and more chemical energy burned than 5.7mm, how come the bullet carries similar amount? that's where momentum (which is m*velocity) comes into play, by conservation of momentum, the .45 recoils much more than 5.7, so more energy is wasted in recoil and goes to gun/shooter

now with about the same energy to begin with for handgun bullets, the efficiency to use that energy is what makes the difference, that's where different rounds/designs play their role, to best use the energy, from energy perspective:

1. you want the bullet to stay inside so no kinetic energy is wasted
2. ideally you don't want the bullet to fragment or deform (if it can do the same amount of damage), since the fragmentation/deformation of bullet itself will use quite a bit of energy, so tumbling is better than fragmentation, energy wise
3. you want to use more energy to tear apart things, not to grind and generate heat, so i'd think pointy nose with "sharper edge" will be better than round nose which is smooth everywhere
 
so tumbling is better than fragmentation, energy wise
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You are assuming too much.

Ideally you do want a handgun or rifle bullet, specifically a Hollow-Point or Soft-Point, to deform or mushroom.

Energy, or energy dump in the target is pretty meaningless in handgun calibers anyway, as there isn't enough in most cases to matter.

You want to use the available energy to deform the bullet, while still having enough left to drive it to sufficient depth to reach the vital organs.

It has been proven for over a century that at handgun velocity, slow large caliber bullets that don't expand, or faster intermediate caliber bullets that mushroom are the most effective at stopping fights.

Energy & high velocity are just not there to get a handgun bullet to work like a high-velocity rifle in wounding capacity.

The two are not in the same class energy wise.

And again, tumbling is not more effective then mushrooming with deep penetration.

The military has to depend on tumbling because they have to use FMJ bullets under the Hague Convention rules of war.

If they didn't, they would get much better killing performance with HP or SP bullets that expand or fragment and continue through the target.

That is why big game hunters use bullets that expand or mushroom instead of FMJ bullets that tumble.

The mushrooming bullet just plain kills game animals quicker and deader.
The same applies to the human animal too.

rc
 
Maybe you've found a market niche.

Pick a caliber you like, get some lead round nose bullets, shave the lead down to a point, load them up and do some experiments.

First weigh your new bullet to see how much lighter it has become, find some load data, and load some rounds. Next check feeding in your auto loader, then check velocity with your chronograph, and calculate energy, then penetration into ballistic gel. Maybe you'll find something that works great and you could make a fortune? I say go for it.
 
1. you want the bullet to stay inside so no kinetic energy is wasted
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You've obviously never seen the damage that occurs from exit wounds on game animals shot with expanding bullets, nor the massive bleeding from an exit wound. You only want the bullet to stay inside to avoid collateral damage.
2. ideally you don't want the bullet to fragment or deform (if it can do the same amount of damage), since the fragmentation/deformation of bullet itself will use quite a bit of energy, so tumbling is better than fragmentation, energy wise
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Wrong. Fragmentation and / or expansion are how the bullet uses its KE to wound. Read the works published by Fackler and Roberts - see below. Better yet, go shoot a deer through the chest with a 55gr Nosler Ballistic Tip bullet out of a .223/5.56. Tell me what you see when you field dress it. The bullet uses its KE to fragment violently, turning the heart and lungs to mush, or "strawberry soup" as a friend likes to describe it. Why do you think every state in the US mandates, by law, that expanding ammunition be used for hunting game?
3. you want to use more energy to tear apart things, not to grind and generate heat, so i'd think pointy nose with "sharper edge" will be better than round nose which is smooth everywhere.
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That flies in the face of what every expert in terminal ballistics states. You really should read up on what Dr. Martin L Fackler and Dr. Garry K Roberts have published. The energy doesn't tear things apart. The energy is the force that allows the bullet to expand or fragment and tear or crush tissue.

Congrats on your PhD in Physics. Perhaps you can use your research skills to learn about terminal ballistics rather than theorizing about them without even a basic understanding of the subject.
 
Sam Cade said:
Cool. What was your thesis?
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about phase separation, certainly not terminal ballistics lol

folks, it's hard for me to go through every point, some arguments go without looking at the conditional phrase i put in there, i never claim i am gun or terminal ballistics expert, but the physics is quite simple actually, the goal of physics is to make complicated things simple, not the other way around. yes how to maximize the use of kinetic energy is more of an art, but the physics is sound.

energy to work with in destruction is kinetic energy and nothing else, they are similar for handgun rounds, energy wasted is energy lost, if you have more energy to play with like 5.56 by all means fragment, but for handgun round may be not, when a 9mm hits steel plate nothing happens, where the energy goes? it is wasted to deform the bullet and generate heat.
 
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"The drag force increases exponentially with velocity"

Below the sped of sound it goes up with the square of the velocity.

It peaks right around the speed of sound, then slowly goes down as the Mach angle decreases above the speed of sound.
 
there is an aspect that has not been mentioned (unless I just missed it, if so, sorry for repeating)

Defensive ammunition is designed to create a wound channel and transfer all of it's energy into the target.

A smaller, faster, pointier projectile is more likely to go through the target.

Sending much of the energy into whatever is behind the target is not only inefficient but dangerous.

This is why cops rarely, if ever, toss a 30.06 under the seat of their car.

This is not an issue when shooting at the white tail. It is when shooting at the bad guy.

If course, as mentioned, body armor has changed the battlefield. NATO is concerned with the battlefield and not concerned at all for civilian defensive situations.
 
In the words of Yogi Berra " In theory, theory and practice are the same, in practice they ain't "
Momentum and Energy both must be conserved however Energy can change form KE does get converted to heat energy and 300-400 ft.lbs. of KE ain't much in the way of heat energy. Momentum is what moves tissue out of the bullets path and keeps it there;).
 
actually in terms of maximizing the use of limited energy, heavier bullet wastes more, because when the bullet hits the target, the momentum has to be conserved as well (just like when it leaves the muzzle), so there's always some "pushing" and moving of the target+bullet, that's energy wasted doing no internal damage. since heavy bullet carries much higher momentum, so the moving of the target is more, more energy is wasted compared to lighter faster bullet. just imagine the extreme, if a bullet is a slow hammer (same energy but way higher momentum), the target will simply be knocked back while no damage is done, all the energy is wasted in the "push back"

so from *purely* energy usage perspective, light and fast bullet uses more energy doing the internal destruction. heavy and slow bullet wasted more energy pushing target back
 
All this theory, KE, and formula talk is making my head spin. Even in today's world of engineering we still rely on testing. That's right, major bullet manufacturers test the heck out of bullet designs at varying speeds, in different medium, and barriers. Designs are altered and retested. Why? Because the formulas as applied do not account for some variables. I've been doing my own engineering for years ..... Just shoot stuff and see what works. To that end the little 22 handgun loads are not as affective as many other pistol calibers. No formula manipulation is proving me otherwise.
 
That's absurd. The difference in momentum between typical service caliber defense loads and 5.7 loads makes the typical loads penetrate better, but does not in any way push a 150-pound human at all.

Coast Guard actually just bumped up the average weight of a person from 145 to 185 pounds.

Mass and the materials involved mean a human hit with any reasonable bullet is not getting pushed anywhere, they're getting a hole poked and crushed through them.

Hit a support structure like the hip and a person may be almost certain to fall, but that's a result of physiological damage and not the bullet pushing the person.
 
ns66 said:
actually in terms of maximizing the use of limited energy, heavier bullet wastes more, because when the bullet hits the target, the momentum has to be conserved as well (just like when it leaves the muzzle), so there's always some "pushing" and moving of the target+bullet, that's energy wasted doing no internal damage. since heavy bullet carries much higher momentum, so the moving of the target is more, more energy is wasted compared to lighter faster bullet. just imagine the extreme, if a bullet is a slow hammer (same energy but way higher momentum), the target will simply be knocked back while no damage is done, all the energy is wasted in the "push back"

so from *purely* energy usage perspective, light and fast bullet uses more energy doing the internal destruction. heavy and slow bullet wasted more energy pushing target back
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ns66,

You might wanna familiarize yourself with a couple of books that offer some very informative terminal ballistic models before going too much further. Give C. Schwartz's Quantitative Ammunition Selection and D. MacPherson's Bullet Penetration a try- these books'll bring you up to speed on the topic and with your physics background both will be within your ability to comprehend.
 
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