Velocity vs. Energy
I am a newbie to ballistics. When is it desireable to have a high-velocity/low-energy load versus a low-velocity/high-engergy load? What about low-velocity/low-energy? (would that be a subsonic load?) What about high-velocity/high-energy?
I've been looking at .357 Magnum as an example. Pro-load has a load that is 1,500 feet per second and 624 foot-pounds. That's the highest combined velocity and energy I've seen on a .357 Mag. They advertise it as a defense load. What are the desireable specs on a defense load vs. a hunting load?
-WW
MOΛΩN ΛABE
"If ever time should come, when vain and aspiring men shall possess the highest seats in Government, our country will stand in need of its experienced Patriots to prevent its ruin."
-Samuel Adams, Patriot/Brewer
I've been looking at .357 Magnum as an example. Pro-load has a load that is 1,500 feet per second and 624 foot-pounds. That's the highest combined velocity and energy I've seen on a .357 Mag. They advertise it as a defense load. What are the desireable specs on a defense load vs. a hunting load?
-WW
MOΛΩN ΛABE
"If ever time should come, when vain and aspiring men shall possess the highest seats in Government, our country will stand in need of its experienced Patriots to prevent its ruin."-Samuel Adams, Patriot/Brewer
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The answers to your questions are complicated.
Energy (or "kinetic energy") is proportionate to the square of velocity. In other words, light bullet at higher speeds tend to have more energy than heavier bullets at slower speeds.
Stopping power, as a rough approximation is proportionate to energy, but things are a lot more complicated than that, since bullet design, caliber, and shot placement are also extremely relevant factors.
Which one you "want" depends on what you are trying to do. High velocity light bullets are good for some things, not good for others. Low velocity heavy bullets are good for some things, not good for others.
Subsonic just means the round is travelling less than the speed of sound (which is around 1100 feet per second at sea level). All bullets no matter how fast they are when they leave the gun, ultimately become "subsonic" at some point. . .(either before they hit the target, or after). Almost every rifle round is supersonic, though many of the slower, heavier pistol rounds are not. Once main advantage to subsonic rounds is that they are somewhat quieter, though this is a bit of an oversimplification I dont want to get into.
Again, in *general* more energy is better for defensive (or hunting) purposes, but there is no free lunch. To get more energy you have to use more powder, get more noise and recoil, more cost, have a bigger heavier and more expensive gun, etc.
If you have too much energy, you run the risk of having a bullet pass right through what you are shooting (maybe risking innocent bystanders) or wasting its energy by not expending it within the target.
There is some overlap between hunting and defense loads, but it depends on what you are trying to "hunt". What's good to shoot a prairie dog probably isn't good for a human and what's good for a Moose isn't good for a human either. What's best for most people for a defensive gun is usually a concealable pistol, which is not the kind of gun you would want to use while hunting.
To answer your specific question, any .357 magnum round that put out 600+ foot pounds of energy with a 124 (or greater) weight bullet at 1500 feet per second would make an extremely powerful defensive round. Statistically, rounds like that (or even slighly LESS powerful) are among the best performing defensive handgun rounds available, and MOST people (including most cops and soldiers) carry less. In many ways that might be "too" powerful since it would have tremendous muzzle blast and recoil. **IF** you were good and knew what you were doing you could use such a round for hunting game as large as deer, though it would probably be inadequate to hunt anything bigger than that, and probably unwise for dangerous game.
Which rounds are the "best" for defense is a very hotly debated and controversial subject that you aren't going to be able to get an absolute answer to. Suffice it to say that as a very broad generalization, the better pistol defense rounds are going to shoot a bullet weighing at least 100 grains and generate at least 350 foot pounds of energy, with some weighing a lot more, and some much more powerful than that. What kind of bullet you use is also an important factor, not just how fast its going.0 -
There is another scale, not used much in the ballistics lingo, but in physics it is a common indicator.
MOMENTUM is M * V
The velocity term is not squared as in Kinetic Energy.
The KE term gets a little foggy to some folks when you push the small bullets at screaming velocities. It may be right on paper,as far as being an equivalent load to slower heavier pills, but it does not fit in many folks 'common sense' terms.
Momentum is always conserved. It is the proof that spoofs the movie scenes. I can stand and shoot my scattergun and it will not blow a man out the window....because I am still standing.
I'm not a reeeal old fart. I still love the 308, but I would rather have lugged around 5.56 weapons and ammo as a grunt.
All this number stuff is fine, but if you can't put the first round in the right spot it means nothing.
If we do not hang together,
We will most certainly hang separately.0 -
A defensive load is one that has a low potential for overpenetration and a high probabialty of a one shot kill/stop. it's employment is primarly at 7 yards or less with the shooter under extreme durress. The muzzle blast/ noise/flash of a full bore .357 125 gr load is awesome. It is also the standard for man-stopper that is the benchmark of handgun defense rounds.
A hunting load has more emphasis on penetration from various angles, exit wounds are not a real consideration, they are desireable in most cases. Hunting distances for a handgun are 25 to 100 yards. Hunting bullets tend to be heavier than defense bullets.0 -
I'm no expert - I'm just a guest here!
We are talking defense here. I assume you are not taking about defense from 100 yds. At 10 yards high velocity isn't that big a deal. If you hit a guy with a .223 going a million feet/sec great. It will go right through him and if you hit something vital he is gone. If you don't he is still standing and will have an attitude. Hit someone with a bowling ball going 10/feet/sec he will be on the ground - probably for a long time.
I just think for close defensive hardware, a 1911 is your best bet. This is from a guy that has a few 357's. Not a bad second choice I believe.
cbxjeff<P>It's too late for me, save yourself. <br>0 -
So if I'm reading all this right...
low velocity/high energy = probably good for defense (although high energy may affect shooter's accuracy due to muzzle blast, recoil, etc.)
low velocity/medium energy = good all-around defense load (with managable muzzle blast and recoil)
high velocity/high engergy = probably better for hunting (given the same issues of the hunter to overcome muzzle blast and recoil)
I'm hoping to find a good all-around load that I could use in my 4" Ruger GP100 for defense and in my 18" Marlin 1894c for potential hunting. Sounds like I would probably wan't a medium velocity with a medium to high energy.
I'm sure I am over-simplifying this. [:D]
Thanks for the responses.
-WW
MOΛΩN ΛABE"If ever time should come, when vain and aspiring men shall possess the highest seats in Government, our country will stand in need of its experienced Patriots to prevent its ruin."
-Samuel Adams, Patriot/Brewer0 -
The FBI Academy Firearms Training Unit has a very good article relating to this subject: http://www.firearmstactical.com/pdf/fbi-hwfe.pdf 0 -
Nice read. So basically velocity (as a factor of penetration) is key. After that the size of the bullet (energy) is just gravy.
Thanks!
MOΛΩN ΛABE"If ever time should come, when vain and aspiring men shall possess the highest seats in Government, our country will stand in need of its experienced Patriots to prevent its ruin."
-Samuel Adams, Patriot/Brewer0 -
quote:Originally posted by WoundedWolf
Nice read. So basically velocity (as a factor of penetration) is key. After that the size of the bullet (energy) is just gravy.
Its not that simple. Penetration is due to a combination of bullet velocity, mass, and design, (not just velocity). Bullet energy is dependent on bullet mass AND velocity, and in fact, velocity is more important than mass. This is the relevant quote from the FBI paper.
quote:Increased bullet mass will increase penetration. Increased velocity will increase penetration but
only until the bullet begins to deform, at which point increased velocity decreases penetration. Permanent
cavity can be increased by the use of expanding bullets, and/or larger diameter bullets, which have
adequate penetration. However, in no case should selection of a bullet be made where bullet expansion is
necessary to achieve desired performance.35 Handgun bullets expand in the human target only 60-70% of
the time at best. Damage to the hollow point by hitting bone, glass, or other intervening obstacles can
prevent expansion. Clothing fibers can wrap the nose of the bullet in a cocoon like manner and prevent
expansion. Insufficient impact velocity caused by short barrels and/or longer range will prevent
expansion, as will simple manufacturing variations. Expansion must never be the basis for bullet
selection, but considered a bonus when, and if, it occurs. Bullet selection should be determined based on
penetration first, and the unexpanded diameter of the bullet second, as that is all the shooter can reliably
expect.
The point is, defensive stopping power is a combination of factors, including velocity, bullet caliber, bullet mass, and bullet design. You need the appropriate combination of all of them, rather than any particular one. Just having "high velocity" isn't enough. Just "large bullet" isn't enough.
With respect to momentum, that is equal to mass times velocity. The IPSC guys call this "power factor", and you could measure it in horsepower, if you wanted to. The point of it is if you have two rounds that give equal energy, the one with the greater momentum is going to be the better round. Invariably this is the the one with the bigger bullet (ie greater mass and usually caliber too). If you have two rounds with similar momentums, the one with greater energy is probably the better one. A good example of this is the old 9mm vs. .45 debate. Standard rounds from both have similar energies, about 350 foot-pounds each. But the .45 shoots a heavier, bigger bullet. . .it has more momentum, and is therefore a better round.
In terms of hunting, the real bottom line is that which round you want depends mostly on what you want to hunt. Ammo that is good for "defense" is usually also pretty good for hunting SMALL game (say 100 pounds or less) at close distances. But conversely ammo that is ideal for hunting larger/dangerous game with a handgun is generally inappropriately overpowerful for defense.
There is nothing wrong with having two kinds of ammunition, one for hunting, and one for defense! If you don't have that luxury (or don't want to bother), you should probably just carry the most powerful ammunition you can, that way you are most likely to "covered" no matter what you end up shooting.
Specific to your question, many authorities consider the .357 magnum from a pistol inadequate for hunting deer (and in fact its even illegal in some jurisdictions), but I think that depends on which deer you are hunting. . .there is a big difference between a 100 pound Southern deer vs a 300+ pound Northern Trophy buck. The .357 magnum, in particular is an extremely inefficient cartridge when fired from a pistol since the bullet leaves the gun before much of the powder gets burned. Take the same round and put it into a long-barreled rifle, and you can get up to 30% more velocity, or nearly twice the energy. Now its an extremely potent round.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.
-Albert Einstein0 -
Some very enlightening information here, guys. Indulge, if you will another greenhorn-ignorant question regarding this post;
"The .357 magnum, in particular is an extremely inefficient cartridge when fired from a pistol since the bullet leaves the gun before much of the powder gets burned. Take the same round and put it into a long-barreled rifle, and you can get up to 30% more velocity, or nearly twice the energy. Now its an extremely potent round."
How true is this for the .44 Remington Magnum? Is it roughly equivalent, considering the relative size of the bullet? Thanks.
-Andy0 -
Hi,
Some very good information on this topic has been presented.
There are three types of ballistics:
1. Interior
2. Exterior
3. Terminal
Your question has to do with exterior ballistics or the path and flight characteristics of the bullet from the time it leaves the muzzle until it impacts the target. Your question also relates to terminal ballasitcs or the behavior of the bullet inside the target.
First, here is the actual formula for computing the kinetic energy of the bullet.
The equation for this energy calculation is:
KE = m*v2/2 = bw*v2/450436 (1)
Where:
KE = Kinetic Energy, ft-lbs
m = bullet mass, slugs
v = bullet velocity, f.p.s.
bw = Bullet weight, grains
While this formula is accurate, it is for the initial time-step only, that is muzzle energy. More complicated mathematics are required to compute the bullet energy with distance and time. You will notice the relationships between mass and the velocity, as has been previously mentioned. In fact, that calculation requires requires differential equations and a computer.
All the variables that apply to make a good defensive load are too numberous to mention and many good ones have already been mentioned. For a practical evaluation of how good a load may be as a defensive load, please look at the link below.
http://www.handloads.com/misc/stoppingpower.asp
The link will lead you to a database compiled by Marshall and Sanow. Marshall and Sanow were NYC detectives who analyzed actual shooting incidents. Through their studies they have compiled data on which combinations of caliber and bullets are the most effective for "one shot stops." "One-shot stops" are defined as one shot from the pistol (or rifle) to disable an assailant and stop the fight. These numbers are not represented by calculations but are a summary of actual incidents.
One of the most effective caliber and bullet combinations resulting in one-shot stops is the 357 Magnum loaded with 125 grain bullets. This combination resulted in a one-shot stop 96% in 96% of the incidents. This is only equalled by the 45 ACP with either 185 or 230 grain slugs. Interestingly, the 44 Magnum only results in one-shot stops in 92% of the incidents. This is due to the variables mentioned previously.
Regards,
Heavyiron
Next,
"If I don't see you nomore on this world, I'll meet you on the next one, and don't be late!" - Jimi Hendrix0
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