PDA

View Full Version : Muzzle Energy: What does it mean ?



Abbas
15-09-2009, 08:50 PM
With our interest in firearms I think it's also imperative that we also focus a little on the ammunition and terminology used. The term "Muzzle Energy" often comes up, quite simply it means:

Muzzle energy is the kinetic energy of a bullet as it is expelled from the barrel (muzzle) of a firearm. It is often used as a rough measurement of the destructive potential of a given firearm or load. The heavier the bullet and the faster it moves, the higher its muzzle energy and the more damage it will do.

http://i262.photobucket.com/albums/ii99/AbbasMalik/Muzzle1.jpg

http://i262.photobucket.com/albums/ii99/AbbasMalik/Muzzle2.jpg

"It must be stressed that muzzle energy is dependent upon the factors previously listed and that even velocity is highly variable depending upon the length of the barrel a projectile is fired from. While the above list mentions some averages, there is wide variation in commercial ammunition. A 180 grain bullet fired from .357 magnum handgun can achieve a muzzle energy of 580 foot-pounds. A 110 grain bullet fired from the same gun might only achieve 400 foot-pounds of muzzle energy, depending upon the manufacture of the cartridge. Some .45 Colt ammunition can produce 1200 foot-pounds of muzzle energy, far in excess of the average listed above."

(Source: Wikipedia)

MIdreesTaj
15-09-2009, 09:23 PM
The heavier the bullet and the faster it moves...

above statment is best understood if its a little elaborated...

i think it should be, heavier the bullet, farther it travels, carries more energy and velocity down range at farther distances(initially a lighter bullet will give more velocity), is still able to punch a pack at longer distances as compared to lighter bullets... have more penetration and have more stability and resistance to winds and common barriers in the field such as bushes/grass etc.

HasanJamshad
15-09-2009, 09:27 PM
Very nice topic and information by Abbas. I will not add anything in muzzle energy as Abbas has put the information very nicely. I will just put another piece of the jigsaw puzzle on board.
A bullet that has higher BC(ballistic coeffecient) will better retain the muzzle energy down the range. Like, if we fire two bullets having same muzzle energy but different BC, the bullet having higher BC value will retain more hitting power down the range and will hit hard.

P.S: A bullet that has higher sectional density and better aerodynamic shape(spitzer, boat tail) lesser air drag will have higher BC value.

MIdreesTaj
15-09-2009, 09:35 PM
the bullet having higher BC value will retain more hitting power down the range and will hit hard.

True Sir! Higher BC bullet will hit harder at longer ranges than a lower BC bullet...
much of which depends on the bullet cross sectional density, its contruction/material.

Malik1
15-09-2009, 09:38 PM
Here are two links to calculate the muzzle energy of any particular weapon

http://www.airhog.com/convert.htm

http://billstclair.com/energy.html

And Oooooops! Mike Hudson has a totally different view. Which says

"While energy calculations may be of value when comparing various loads in a single caliber or similar calibers, they can be worse than useless when comparing different calibers and different hunting situations. To illustrate the point, let's examine a couple of rounds, one being a wildly popular high velocity round in wide use today and the other being an outmoded and forgotten dinosaur.

The .243 Winchester fires a 95 gr. spitzer bullet at 3100 fps in one popular hunting load, producing 2021 ft. lbs (The reader may like to calculate the result using the first site mentioned by me. The calculation is by and large correct for both the rifles) of muzzle energy in the process. Many thousands of hunters arm themselves with .243 rifles and kill an inordinate number of deer and antelope every year. (Thereby demonstrating its effectiveness for such use. The .243 is also quite popular in Africa for hunting game animals of similar size. -Ed.)

On paper, the .243 also stacks up great against an old cartridge like, say, the .303 Savage, which launches its flat nosed, 190 gr. slug at a MV of 1980 fps and achieves a paltry 1650 ft. lbs. of energy at the muzzle. The informed observer might further note that the old Savage round is obsolete, meaning it isn't loaded by any of the major ammunition manufacturers anymore, and that rifles chambered for it haven't been manufactured in many years.

Based on this alone, it would be easy to conclude that the .243 is the far better game getter in most, if not all, hunting applications. As with most easy conclusions, however, this one depends entirely on the application and situation.

A lot of factors may have played a role in the ascent of the .243 and the casting aside of the .303 Savage, but muzzle energy shouldn't have been one of them. Experience has shown that, at ranges of less than 150 yards where trajectory isn't much of a factor, a hit from a 190 gr. soft point slug is going to bag a lot of game. At those ranges and on game larger than pronghorn antelope and medium size deer, a well placed shot from the old .303 beats a well placed shot from the .243 every time.

Think about it. While neither caliber would be appropriate for dangerous game, if you found yourself suddenly and uncomfortably up close and personal with a grizzly bear, would you feel better with a .303 or a .243 in your hands?

Out past 200 yards, the .303's rainbow trajectory comes into play and the less than aerodynamic shape of its bullet compounds the effects of gravity. It is only then that the flat shooting characteristics of the .243 come into play.

Such comparisons could be made all day, and are not meant to denigrate the many sportsmen around the world who have chosen the .243, or any other caliber, as suitable for their purposes. They are used merely to point out that fallacy of using muzzle energy, or any other purely theoretical consideration, as some kind of be all and end all when it comes to killing power. " ( Mike Hudson - http://www.chuckhawks.com/myth_muzzle_energy.htm )

Skeeter60
15-09-2009, 09:40 PM
HJ
Nicely summed up the retained energy at longer ranges.

All bullets are deflected after hitting even a thin twig or even a leaf. High velocity bullets with thin jackets (varmint bullets) at high velocity even start to disintegrate a few yards after hitting a a twig etc examples 22-250; 220 swift; 270, 120 gr; 308 ,130 gr etc

12GAUGE
16-09-2009, 01:31 AM
AoA everybody

I would like to add:

the muzzle energy of a typical 00 buckshot load (2.75 inch cartridge) fired from a 21 inch barrel is equal to 1590 ft.lbs. that is equal to 2156 joules.

the muzzle energy of a typical foster type 437grains slug (2.75 inch cartridge) fired from a 21 inch barrel is equal to 2361 ft.lbs. that is equal to 3201 joules.

any rifle or pistol can result in a person pushing up daisies, but only a shotgun makes sure that even in heaven that person ends up with 9 holes in his chest. BOOM SHAKA LAKA.

Regards.

Abu Hafs
16-09-2009, 02:29 AM
@bro 12 gauge


Taking the vast muzzle energy produced by a shotgun into consideration why the lack of penetrative prowess of shotgun ammo as compared to bullets which carry relatively less energy, not including the solid slugs obviously?

12GAUGE
16-09-2009, 07:36 PM
@bro 12 gauge


Taking the vast muzzle energy produced by a shotgun into consideration why the lack of penetrative prowess of shotgun ammo as compared to bullets which carry relatively less energy, not including the solid slugs obviously?


its pretty simple:

first: the muzzle energy of a shotgun is calculated using all the projectiles in a load setting.

second: shotgun projectiles are usually round balls instead of conical shapes of a typical rifle bullet. hence lesser penetration.

third: slug, which is basically a single projectile, acts just like a rifle bullet during its flight. therefore it exibits tremendous penetration, infact over penetration/devastation. but since its heavy and blunt, its range is severly limited compared to a rifle. but quiet alot when compared to a typical buckshot load.

Regards.

Abu Hafs
16-09-2009, 08:42 PM
Excellent response as always 12gauge, Thanks bro.

12GAUGE
17-09-2009, 12:26 AM
Excellent response as always 12gauge, Thanks bro.


you are most welcome brother.


Regards.

Slayerjatt
18-09-2009, 01:38 AM
very informative. thanks to all our esteemed senior members for sharing the knowledge.