bullet weight vs. velocity regarding ME

[simonrichter]

what are the advatages / disadvantages of loads gaining their muzzle energy largely from heavier bullets as compared to those more relying on velocity?

E.g. some 5,7 loads may have the same ME as some .45 acp ones, still of course they have completely different properties in terms of inner, outer and terminal ballistics (are these the proper English terms, by the way?)...

I have already elaborated the differences in terms of outer ballistics: A lighter, faster bullet will have a rather flat trajectory, but is much easier disturbed by anything it hits on its flight path. A heavier, slower bullet is as such limited in its range because of the quickly increasing drop, but within its range it's less prone to deflection. Did I get that straight?

So what about inner ballistics (felt recoil, required barrel lenght, muzzle flash) and terminal ballistics (penetration, energy transfer etc.?)

 

[db4570]

Get ready for a long argument here from both camps. This is the eternal question among gun guys. Big and slow, or light and fast?

The classic comparison might be 9mm vs. 45 ACP. Both have similar muzzle energy. Fans of 45 ACP often seem to feel that nothing can touch the effectiveness of their big, heavy bullets.

From studying big game cartridges for many hours, I think I have come to the conclusion that light/fast bullets seem to do a lot of spectacular damage when things go right, but things fall apart when the going gets tough. Deflection, core separation, etc. Heavy/slow keeps plowing through. Which is why elephants are hunted with .458 Magnums and not .300 Magnums.

Me, I like the best of both characteristics, which is why .357, 10mm, and 40 appeal to me. But I own 9mm and 380. Go figure.

David

 

[Aguila Blanca]

We're in the handguns area, so long-range velocity loss probably doesn't matter. But, for the geek types, remember that E=MC^2 (energy = mass times velocity squared). Bullet mass remains the same throughout the trajectory, so there's no reduction in energy downrange due to loss of mass. But velocity degrades, and the energy loss is the square of the velocity loss.

Velocity is not going to drop by half but, if it did, the energy at half the muzzle velocity would be only one-quarter of the muzzle energy.

 

[Wyosmith]

Both bullet weight and velocity are factors, but so is bullet shape and design.
If you look at the 100 yard "energy' of a 22-250 and a 45-70, you will see the 22-250 has more theoretical "foot pound" of energy.

But the 22-250 with a frangible 55 grain bullet is a very poor buffalo rifle. Millions of American bison were killed (and killed very well) with 45-70. And it's as good today as it was in the 1880s.

In handguns the faster bullet will usually beat the slower bullet of the same weight. But not always. And also the factor that is by far the most important is often overlooked. That factor is marksmanship.
A smaller and milder pistol or revolver is easier to fire accurately than a big powerful one. This is not to say that a man or woman cannot learn to shoot a big magnum as well. they can and some do. At one time I was a VERY good shot with a 44 magnum and a 454 Casull, But in those days I was shooting every day.
I am the former CEO of Cast Performance Bullet company. When I was with that company I often fired 1000-2000 round a week and I do so for years. Anyone will become a good shot if you get to shoot at much.

But the human factor must not ever be ignored. In hunting with rifles it is accepted that a good hit with a 6.5 Swede is far more effective than a poor hit with a 340 Weather by. Why would handguns be any different?

If you want a technical overview it's pretty easy to describe. Given bullets that hold their weight, and don't become a "Shot Charge" (by breaking into pieces) Bigger is better and faster is better, and bigger+ faster is WAY better, but bigger+faster come at a cost.
Bigger guns.
Heavier guns.
Much harder to control.
Much harder to carry.
Often a liability because the power can do damage to things and people that are on the other side of the target.

If this were not so we all would carry 378 Weatherby Magnums as personal defense weapons. But they kick,-----and don't fit well in a holster.

All joking aside, the thing to do is to get a gujn of good quality and use loads you can shoot well. then shot it a LOT and learn to shoot it VERY well. If you want more power you can get another gun later.

Also be sure to match your gun and your load to the mission statement. By that I mean you try to have a combination that is the most likely to be what is needed.
If you live in a town full of criminals I'd assume you can do will with a 44 Magnum or a heavy loaded 45 colt, but a 45 auto or a 9MM might fulfill the mission statement of "personal defense weapon in urban area" better. 44 Magnums will work on human enemies, but they also work very well on elk. Humans are smaller than elk.
If on the other hand you live somewhere like I do, where humans are fairly rare and elk, bears deer and antelope are common as well as a lot of coyotes and fox, skunks and raccoons, a 44 magnum is going to be what is more useful in most cases. if I was to have to defend myself against a human enemy I am pretty sure the 44 will do fine. Because of its capacity of 6 rounds and slower reload time, it would not be as good a choice as an auto pistol for a cop, but I am not a cop and I hope that I don't have to fight 10 men at one time with a revolver. But I do shoot animals quite often, and I fight for my life ...........well........it's been a very long time since I had to do that. Like about 30 years now.

Anyway, this rambling is not 100% worthless,,,,, (maybe only 90%) but I am trying to point out that the human factor is way more important than the mechanical factors. Before you select a load for any given caliber define the mission statement.
What do you want to do with the gun MOST of the time?

Power is transferred in 2 ways to targets.
#1 is penetration. (how deep is the hole)
#2 is cavitation. (how big around is the hole)

More is more, but not always better. What is better depends on the mission statement.

 

[44 AMP]

inner, outer and terminal ballistics (are these the proper English terms, by the way?)...

we generally use the terms "internal" and "external", but I understand what you mean.

Calculated energy changes radically with changes in speed (velocity squared). but it is important to keep in mind that energy figures (ft/lbs) are only a method of comparison, and NOT then entire reason for a bullet working well for a particular target, or not.

 

[T. O'Heir]

"...these the proper English terms..." Close enough. Like 44 Amp says, it's internal and external. That being in the barrel and after exiting. Different forces at work with both.
"...Big and slow or light and fast..." And big and fast. A .45 is big and slow. 9mm is light and fast. A .44 Mag is big and fast.
"...E=MC^2..." It's E=MC*2. Also close enough. However, it's that Newton fellow's Third Law that applies to felt recoil. Heavy stuff going at the same speed as lighter stuff in a like firearm produces more felt recoil. It's the Law!!!. snicker.
There's no real advantage or disadvantage to either.

 

[azkid]

"...E=MC^2..." It's E=MC*2. Also close enough.

I'm case it helps (forgive me; first post), energy, E, is equivalent to half the mass times the square of velocity. E=(1/2)mv^2 (cf. https://en.m.wikipedia.org/wiki/Kinetic_energy)

I imagine force (from air drag or impact) and deceleration have to play in; F=ma so negative acceleration (deceleration) from a given force is inversely proportional to mass. That is, more mass requires more force to decelerate. Force of impact or air drag to slow a bullet is dependent on bullet diameter in simplistic terms but as said above also on shape (enter: sectional density, ballistic coefficient...)

But... It seems to me that effectiveness of a bullet is wildly more complicated than all this. Or else all the long-raging debates (lookin' at you, 9mm vs .45acp) would have simply faded away to simple chalkboard calculations years ago

 

[BigJimP]

In my view you should pick a cartridge based on what you want to do with it....and how well you can shoot that cartridge ( with your experience, amount you practice, etc ) ....but as I've gotten older I'm not as big a fan of heavy recoil.../ and with the primary recoil factors made up of weight of the gun, weight of the bullet and velocity of the bullet...to do the job for "Personal Defense" .. I want "Tactical Accuracy" ...with good split times between my shots...so, for a given caliber...

a. in a lighter gun with a shorter barrel.../ I will want a lighter bullet at a mid range velocity ...
b. in a heavier gun with a longer barrel.../ I will want a heavier bullet at a faster velocity...or a lighter bullet at a higher velocity
Example ... full power .44 Mag 240 gr bullets ...are not easy for me to shoot in a revolver with a 3" barrel ..vs a 6" barrel where it is a lot easier / full power .45 acp in a 230 gr bullet ...are easier to shoot in a steel 1911 with a 5" barrel than an alloy frame 1911 with a 3 1/2" barrel...

a few ounces of weight in the gun ...and 1/2" longer barrel makes a real big difference to me..../ and how it fits my hands, etc...way more than the bullet I choose ...

 

[jmr40]

. Millions of American bison were killed (and killed very well) with 45-70. And it's as good today as it was in the 1880s.

Virtually all the buffalo were killed before the Civil War by an extended drought during the 1850's. Buffalo hunters using large bore muzzle loaders sped things up. The 45-70 was introduced in 1873. Laws were passed in 1874 banning buffalo hunting to preserve the handful left.

There may have been a few buffalo killed illegally with 45-70, but in the 1880's it was considered borderline for anything larger than whitetails. By the late 1890's it was all but dead and the 30-30 was considered much more powerful. It remained dormant and virtually unused until Marlin re-introduced the 1895 rifle in 1973 with a lot of colorful advertising.

The goal of any bullet is to penetrate deep enough to reach vital organs. If it can be made to expand then great, but that is really secondary. Muzzle energy is one tool that can be used to help predict bullet penetration and expansion. But it is not perfect. If understood and the data applied correctly ME can be a useful tool. But looking at other data is more important.

Either approach, small and fast or large and slow, can be effective. Or either can fail depending on a lot of other factors. 9mm ammo will penetrate just as much as 45 in humans. As long as vital organs are hit the end results are the same. The bullet used is far more important than caliber. You will find very few who get paid to carry a gun for protection who buy into the 45 legend anymore. If the 9mm gives the same end result, why put up with greater expense, recoil and reduced ammo capacity.

 

[44 AMP]

It remained dormant and virtually unused until Marlin re-introduced the 1895 rifle in 1973 with a lot of colorful advertising.

Unused enough that ammo remained in constant production, and still is.

Not one of the top 5 (or whatever) most popular rounds for a long time, but in constant use since 1873, with a big revival (nostalgia) at the 100 year mark that continues today.

 

[Aguila Blanca]

"...E=MC^2..." It's E=MC*2.

No, it's not E=MC*2. If you don't have subscript and superscript characters in your font, such as when entering formulae in Excel, the asterisk (*) indicates multiplication. The caret symbol (^) indicates raising the number to the power indicated by the number following the symbol.

E=MC^2 is the way to express the formula in Excel, and enough people use Excel that it's generally understood where we don't have access to superscript fonts.

 

[Aguila Blanca]

I'm case it helps (forgive me; first post), energy, E, is equivalent to half the mass times the square of velocity. E=(1/2)mv^2 (cf. https://en.m.wikipedia.org/wiki/Kinetic_energy)

I don't think so. That would be E=(M/2)C^2

http://www.emc2-explained.info/Emc2/Equation.htm

 

[45_auto]

remember that E=MC^2

The only time that E = MC^2 is if you convert all of the bullet's mass into energy. I very seriously doubt if you're shooting nuclear explosions out of your pistol (unless you're shooting a 10mm).

The constant "C" in the above equation is the speed of light in a vacuum, about 983,571,056 feet per second.

The equation that everyone seems to be looking for in relation to your handgun is the equation for kinetic energy:

E=1/2 mass times velocity squared

E = (M/2)*V^2 (NOT "C", C is the speed of light)

 

[mehavey]

- Kinetic Energy of a moving mass = ½mV^2 (where V is its velocity)

- Ultimate Atomic Energy in any mass (moving or not) = mC^2 (where C is the speed of light)

 

[Branko]

Often you'll have, in the same catridge, a "light and fast" and "heavy and slow" option, and often enough they'll have the same or similar enough muzzle energy. So, what are the advantages / disadvantages of each?

The heavy and slow option has more momentum, and when it comes to penetrating flesh (or liquids), assuming the same caliber and nose shape, it will have better penetration for the same muzzle energy. Penetration in liquid is generally a factor of momentum (which is simply mass*velocity) and some bow and arrow researchers (where the same discussion surfaces) suggest that m*v^1.2 is the relevant factor for penetration in flesh.

For penetrating hard barriers (eg, metal, etc) you are interested in kinetic energy (mv^2 / 2), or chiefly, increasing velocity, other things being the same. Hence high velocity pistol rounds, like 7.62x25mm Tokarev or some NATO 9mm FMJ rounds are able to penetrate lower class vests which would stop a larger bore projectile moving slower which would have an equal penetration in flesh or ballistic gel.

Shooting at range - the high speed lightweight round will have a flatter trajectory (meaning more effective at hitting), but all factors being the same the lower speed heavier round will often retain more penetrating power in flesh. Recoil? For the same muzzle energy, heavy and slow will recoil "more", because momentum has to be the same both ways.

As for effectiveness, both light and fast and heavy and slow will be effective with proper shooting and sufficient penetration for the task. Since with handguns velocities which result in hydrostatic shock (as you'd get with a fast rifle round) just aren't going to happen, the primary method how it works is tissue damage. Both light and fast and heavy and slow will give penetration just fine, but sometimes speed is required for it to expand with reliability.

It's pretty easy, really, to get the required penetration; a .158 gr round nose lead .38 special, considered a not very good catridge, will penetrate around 20" of ballistic gel (more or less, depending on barrel length) which is more then enough and puts it in territory of overpenetration, but the wound channel is small. It will still work if the vitals are directly hit, just like it and similar catridges did for about a 100 years prior to modern catridges.

Modern self-defense or police rounds will penetrate less, but will expand and cause a wider wound channel, which will work much better, however to get reliable expansion (alongside with sufficient penetration), extra velocity is required. Hence, most of the ammo geared for these purposes nowadays is +P something and on the light side, for this reason.

 

[buckhorn_cortez]

E=MC^2 is Einstein's mass-energy equivalence formula and is usually applied to STATIONARY objects (zero inertia) to describe its "rest energy."

In 1905, Einstein proposed the question "Does the inertia of a body depend upon its energy content?"

The answer in words is - "If a body gives off the energy L in the form of radiation, its mass diminishes by L/V^2." (In the original formula, L = energy lost and V = speed of light in a vacuum.)

Obviously, this has NOTHING to do with bullet ballistics, and everything to do with the conservation of mass / energy, or converting mass directly to energy meaning - nuclear reactions.

 

[JERRYS.]

muzzle flash is a result or can be diminished by the powder used.

an easy formula for muzzle energy is: velocity X velocity, X bullet weight in grains, Divided by a constant of 450436 Equals kinetic muzzle energy.

I.E. (850 fps x 850 fps = 722500, times 230 grains = 166175000. now divide that by 450436 and you get 368.9 foot pounds of energy.

muzzle energy is not an end all solution and most of the others here have already touched on the issues of penetration, and expansion based on bullet design....

 

[simonrichter]

we generally use the terms "internal" and "external", but I understand what you mean.

thanks, that was obvious, now you say it. Seems I somewhat just directly translated the German terms...

And thank y'all for the interesting insights so far!

PS:

Divided by a constant of 450436

> thats why in that case I definitely prefer metric measures

 

[45_auto]

thats why in that case I definitely prefer metric measures

You think that dividing by the 30822 constant used in the metric system to easily calculate energy in joules given weight (grains) and velocity (meters/sec) is somehow easier or superior to dividing by the 450436 constant used in the English system to easily calculate energy in ft-lb given weight (grains) and velocity (ft/sec)?

 

[SSA]

230 gr @ 828 fps = 350 ft-lb ke
124 gr @ 1128 fps = 350 ft-lb ke
31 gr @ 2255 fps = 350 ft-lb ke

The 45 or the 9mm can be made to penetrate about 15" of ballistic gel with a jhp, but will penetrate more than that with a fmj. The 5.7 can be made to penetrate less in gel with the same ke, when a fmj is required.

One possible advantage of the 5.7.