Energy formula

08 October 2009, 23:47

Michael Robinson

If you really want to be able to do it longhand, here is the formula:

PKE = ((½ x PW/GC) x PV^2) ÷ 7000

Where:

PKE = Projectile kinetic energy in foot-pounds.
PW = Projectile weight in grains
GC = 32.174 (the gravitational constant for earth in feet per second per second)
PV = Velocity of projectile in feet per second
^2 means "squared"
7000 = Number of grains per pound

So, for one of my favorite .500 A-Square hunting loads, namely, a 570 grain bullet with a muzzle velocity of 2,525 feet per second, the muzzle energy would be calculated as follows:

ME = ((½ x 570/32.174) x 2,525^2) ÷ 7000
ME = ((½ x 17.716) x 6,375,625) ÷ 7000
ME = (8.858 x 6,375,625) ÷ 7000
ME = 56,475,286 ÷ 7000
ME = 8,068 ft.-lbs.

09 October 2009, 01:39

Will

quote:
ME = 8,068 ft.-lbs.

Now here is too much gun!!

-------------------------------
Will / Once you've been amongst them, there is no such thing as too much gun.
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09 October 2009, 01:52

Biebs

Too much energy??? No such thing :-)

09 October 2009, 07:12

Michael Robinson

quote:
Originally posted by Will:
quote:
ME = 8,068 ft.-lbs.

Now here is too much gun!!

Perish the thought!

09 October 2009, 07:36

buffybr

quote:
Too much energy??? No such thing :-)

Remember, for every action there is an equal and opposite reaction. Recoil

09 October 2009, 10:33

bigdoggy700

That why they put a big butt stock on a 500 a square. I have shot mine with 600 grain bullets at 2630 ft/sec. for 9216 ft.lbs of energy. Thats about max for me out of the 500 A Square. energy formula bullet wt. in grains times velocity in ft/sec times velocity in ft/sec, all divided by 450,300 = ft.lbs of energy.

09 October 2009, 10:51

500N

8000 ft lbs is not that bad.

I find once it hits 10,000 ft lbs, that's when
I find my limit !!!

11 October 2009, 04:41

SR4759

quote:
Originally posted by 500N:
8000 ft lbs is not that bad.

I find once it hits 10,000 ft lbs, that's when
I find my limit !!!

This is just the big bore wannabe crowd.

12 October 2009, 11:40

Michael Robinson

quote:
Originally posted by SR4759:
quote:
Originally posted by 500N:
8000 ft lbs is not that bad.

I find once it hits 10,000 ft lbs, that's when
I find my limit !!!

This is just the big bore wannabe crowd.

Okay. Here's the deal.

You get me a Form 4457 for that Solothurn, then get it through check in at Logan airport (including paying the excess baggage allowance!), and then carry that Swiss miss, plus ten rounds of her 20 mm AP ammo, for ten hours plus, over 10 or 12 miles, in 100 degree Fahrenheit heat . . .

And then, if we can find a big enough bull elephant (no guarantees!), and also -- if you'll be my shooting sticks and allow me to rest that 20 mm monster on your shoulder - well, then, I say - that is, then - and only then - I'll shoot that big bull elephant with that Big Bertha!

And maybe, just maybe, not be undergunned!

Okay?

Hell, if I could've, I would've done it by now!

It's just that the practical tends to rear its ugly head from time to time!

12 October 2009, 23:57

SR4759

quote:
Originally posted by mrlexma:
quote:
Originally posted by SR4759:
quote:
Originally posted by 500N:
8000 ft lbs is not that bad.

I find once it hits 10,000 ft lbs, that's when
I find my limit !!!

This is just the big bore wannabe crowd.

Okay. Here's the deal.

You get me a Form 4457 for that Solothurn, then get it through check in at Logan airport (including paying the excess baggage allowance!), and then carry that Swiss miss, plus ten rounds of her 20 mm AP ammo, for ten hours plus, over 10 or 12 miles, in 100 degree Fahrenheit heat . . .

And then, if we can find a big enough bull elephant (no guarantees!), and also -- if you'll be my shooting sticks and allow me to rest that 20 mm monster on your shoulder - well, then, I say - that is, then - and only then - I'll shoot that big bull elephant with that Big Bertha!

And maybe, just maybe, not be undergunned!

Okay?

Hell, if I could've, I would've done it by now!

It's just that the practical tends to rear its ugly head from time to time!

Practical depends upon your frame of reference.
Money and determination can solve all of the problems you mentioned.

Ship the gun ahead.
Hire a crew to carry it. It is a crew served weapon.
Spend a month finding your elephant.
It is not like you have to stalk within 50 yards.