Muzzle Energy

[vytoland]

when i look at various vendor ads for ammunition, specifications for bullet weight, muzzle velocity and muzzle energy are listed. i undersatand how the bullet weight and velocity are measured, but how is energy calculated?

[rocket12]

Energy(Ft-#)=(Velocity(in FPS) Squared)*(weight (in pounds))/(2*32.2)

[tom234]

Just plug in the numbers......
http://www.handloads.com/calc/quick.asp
http://www.realguns.com/calculators/kineticenergy.html

[Shoney]

tom234
In your appendid sites, they use the PHD approach to yield the E.
They do not tell you how to figure it or why, they have you Put it Here Dummy.


Very well put answer rocket12.

[Gun 4 Fun]

Just remember, muzzle energy is not a good way to compare a rounds potential or killing ability. Muzzle energy highly favors velocity, double bullet weight and you double energy-double bullet speed and you quadruple energy.
An example: the 22-250 with a 55 gr. bullet at approx. 3650 feet per second, has around 1800 foot pounds of energy at the muzzle. A 45/70 with a 405 gr. bullet at approx. 1300 fps, has about 1500 foot pounds of energy. Which do you think would kill a moose, bear, elk, etc. better?

[ryalred]

guns 4 fun
you make a very good point, but if you were comparing say, a .257 Roberts with a .257 Wby magnum (same caliber guns) and you wanted to know which had the best long range potential you'd have to go with the .257 Wby Mag. Both shooting a 120 grain Nosler Partition--at 400 yds the .257 Wby Mag has an impressive 1471 ft-lbs of energy while the Roberts has only 1030 ft-lbs of energy. Which would you rather shoot a whitetail deer with at 400 yds? For that matter, you could compare the .257 Wby Mag. to the .45-70 at 400 yds. The .45-70 has only about 800 ft-lbs of energy at that distance. Which would you rather shoot the whitetail deer with? In this case, I'd choose the .257 Wby Mag with the much higher energy (not to mention the fact that I'd have a MUCH better chance of hitting the deer with the .257 at that distance). So, it seems to me that energy does come into play in choosing a rifle in some situations. This can get into that discussion of bigger and slower, versus smaller and faster. But I would agree with you about rather having the .45-70 for large game than the .22-250.

[WESHOOT2]

I do not find energy to be a meaningful figure.

[Sevens]

but if you were comparing say, a .257 Roberts with a .257 Wby magnum (same caliber guns) and you wanted to know which had the best long range potential you'd have to go with the .257 Wby Mag. Both shooting a 120 grain Nosler Partition--at 400 yds the .257 Wby Mag has an impressive 1471 ft-lbs of energy while the Roberts has only 1030 ft-lbs of energy. Which would you rather shoot a whitetail deer with at 400 yds?

While indeed this is true, do you REALLY need to bring up energy to find the answer to your question? Given that it's the same exact bullet, there is no complicated math involved. You take the one that goes faster at the muzzle and you'll have the one that goes faster at 400 yards.

I agree that velocity is over rated and bullet weight and sectional density are very much under rated in the energy formula. But I won't go as far as to say that it's a useless figure.

Muzzle energy highly favors velocity, double bullet weight and you double energy-double bullet speed and you quadruple energy.

That's the most useful thing to remember in this discussion, IMO.

[joneb]

http://www.thefiringline.com/forums/...orce+on+impact