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Joined: Jun 2001
Posts: 19,106 Likes: 5
Campfire Ranger
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Campfire Ranger
Joined: Jun 2001
Posts: 19,106 Likes: 5 |
Might be useless, but Colorado uses it to determine the legality of hunting rifles. 1000 ft lbs at 100yards for rifles and 500 ft lbs at 50 yards for handguns.If you all think it is meaningless,try arguing with a game warden when you are using a .357 mag handgun
If God wanted you to walk and carry things on your back, He would not have invented stirrups and pack saddles
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Joined: Nov 2008
Posts: 2,081 Likes: 1
Campfire Regular
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Campfire Regular
Joined: Nov 2008
Posts: 2,081 Likes: 1 |
Just to be a nit picker...... The divisor 450,240 was change back in the late 60's or early 70's to 450,400. Apparently a group of physicists determined the results of using the earlier number didn't quite line up with some newer or more complete observations. Or so I was told a physics professor in college. The difference in the end result, at least as far as we're concerned, is extremely small...about 1 foot pound with a 30/06 180 grain factory load.
Last edited by MickeyD; 02/27/20.
~Molɔ̀ːn Labé Skýla~
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Joined: Aug 2009
Posts: 96,162 Likes: 3
Campfire Oracle
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Campfire Oracle
Joined: Aug 2009
Posts: 96,162 Likes: 3 |
I use this formula.....
Bullet weight x velocity x velocity ÷ 450240
Example... 300 x 2750 x 2750 ÷ 450240 = wabbit pounds. Elkster's formula.
Life Member SCI Life Member DSC Member New Mexico Shooting Sports Association
Take your responsibilities seriously, never yourself-Ken Howell Proper bullet placement + sufficient penetration = quick, clean kill. Finn Aagard
Ken
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Joined: Aug 2009
Posts: 96,162 Likes: 3
Campfire Oracle
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Campfire Oracle
Joined: Aug 2009
Posts: 96,162 Likes: 3 |
I use this formula.....
Bullet weight x velocity x velocity ÷ 450240
Example... 300 x 2750 x 2750 ÷ 450240 = 5038 foot pounds. Thanks Elks. I have the equation for converting CUP to PSI - courtesy of Mr. Denton and the equation to determine Bore Capacity. I have LOST & forgotten that equation. I'm putting it in My Phone Reminder Page. Thnx Jerry You're Jwall.
Life Member SCI Life Member DSC Member New Mexico Shooting Sports Association
Take your responsibilities seriously, never yourself-Ken Howell Proper bullet placement + sufficient penetration = quick, clean kill. Finn Aagard
Ken
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Joined: Oct 2001
Posts: 285
Campfire Member
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Campfire Member
Joined: Oct 2001
Posts: 285 |
Just to be a nit picker...... The divisor 450,240 was change back in the late 60's or early 70's to 450,400. Apparently a group of physicists determined the results of using the earlier number didn't quite line up with some newer or more complete observations. Or so I was told a physics professor in college.. He probably owes you a refund on at least part of your tuition. There is no one person, entity, or group who decides on the value of that constant,-- it is the combination of two other numbers, one of which is well defined and the other is pretty well defined, sorta. Kinetic energy is 1/2 m v^2. To get it in ft-lbs, you have to divide by 7000 to convert grains to pounds, and you have to divide by the acceleration due to gravity to get from slugs to foots. Standard gravity is about 32.17405 ft/sec^2, although it actually varies from place to place. So, 2 x 7000 x 32.17405 = 450,436.7 But, feel free to use anything close that you can remember. As noted, it doesn't change the result very much. But if you remember what the number is and why it is, then you can easily get the exact number anytime you want it. Enjoy,
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Joined: Dec 2004
Posts: 3,639
Campfire Tracker
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Campfire Tracker
Joined: Dec 2004
Posts: 3,639 |
In the formula E=MC2 the "C" stands for velocity of light in meters per second. (300,000,000) and "M" is for mass in the metric system. This is difficult to apply in the English system but E=1/2KMV2.....here the "M" is for mass but the unit of mass in the English system is a slug.....or 32 pounds.
If we are to use grains and feet per second then we convert the "M" by dividing by 32 and again by 7,000 (number of grains in a pound)
because the constant "K" is 1/2 we again multiply like this.....7,000 X 32 X 2 = 448,000
Assuming a velocity of 3,000 feet per second (squared) we get 9,000,000 and times the weight of the bullet (lets assume 150 grains) we get 3,000 X 3,000 X 150 = 1,350,000,000 Divide that by the 448,000 we get 3,013.3928 foot pounds.....check this with the 150 grain load of a .30-06
The previous number used (450,240) is likely a tad more accurate as the numbers I used are very slightly rounded but are close enough for the kind of girls I go out with.
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Joined: Sep 2010
Posts: 19,179
Campfire Ranger
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Campfire Ranger
Joined: Sep 2010
Posts: 19,179 |
Thanks Elks.
I have the equation for converting CUP to PSI - courtesy of Mr. Denton and the equation to determine Bore Capacity.
I have LOST & forgotten that equation. I'm putting it in My Phone Reminder Page. Thnx Jerry
You're Jwall. Why Yes, I am !
jwall- *** 3100 guy***
A Flat Trajectory is Never a Handicap
Speed is Trajectory's Friend !!
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Joined: Jan 2010
Posts: 6,240 Likes: 4
Campfire Tracker
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Campfire Tracker
Joined: Jan 2010
Posts: 6,240 Likes: 4 |
How many foot lbs of energy does a 3 ounce scalpel moving 1" every minute have?
Quit giving in inch by inch then looking back to lament the mile behind ya and wonder how to preserve those few feet left in front of ya. They'll never stop until they're stopped. That's a fact.
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Campfire Ranger
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Campfire Ranger
Joined: Sep 2010
Posts: 19,179 |
How many foot lbs of energy does a 3 ounce scalpel moving 1" every minute have? NONE, if I get my 40 out quick enuff. just joking fellows. Jerry
jwall- *** 3100 guy***
A Flat Trajectory is Never a Handicap
Speed is Trajectory's Friend !!
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Joined: Dec 2004
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Campfire Tracker
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Campfire Tracker
Joined: Dec 2004
Posts: 3,639 |
Thanks Elks.
I have the equation for converting CUP to PSI - courtesy of Mr. Denton CUP and PSI are two different things and there IS NO FORMULA to convert one to the other. Mr Denton has done a pretty fair job of estimating one in terms of the other over a short range and I congratulate him for the effort. He's fairly close....but again over a short range.
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Joined: May 2004
Posts: 56,194 Likes: 18
Campfire Kahuna
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Campfire Kahuna
Joined: May 2004
Posts: 56,194 Likes: 18 |
I been killin' pigs with 35 fpe? How is that possible?
I am..........disturbed.
Concerning the difference between man and the jackass: some observers hold that there isn't any. But this wrongs the jackass. -Twain
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Joined: Aug 2009
Posts: 96,162 Likes: 3
Campfire Oracle
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Campfire Oracle
Joined: Aug 2009
Posts: 96,162 Likes: 3 |
Thanks Elks.
I have the equation for converting CUP to PSI - courtesy of Mr. Denton and the equation to determine Bore Capacity.
I have LOST & forgotten that equation. I'm putting it in My Phone Reminder Page. Thnx Jerry
You're Jwall. Why Yes, I am ! Long day for me today. "You're welcome Jwall" is what I should have wrote.
Life Member SCI Life Member DSC Member New Mexico Shooting Sports Association
Take your responsibilities seriously, never yourself-Ken Howell Proper bullet placement + sufficient penetration = quick, clean kill. Finn Aagard
Ken
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Joined: Dec 2004
Posts: 3,639
Campfire Tracker
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Campfire Tracker
Joined: Dec 2004
Posts: 3,639 |
I been killin' pigs with 35 fpe? How is that possible? What are you using?.....
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Joined: Sep 2010
Posts: 19,179
Campfire Ranger
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Campfire Ranger
Joined: Sep 2010
Posts: 19,179 |
CUP and PSI are two different things and there IS NO FORMULA to convert one to the other.
Mr Denton has done a pretty fair job of estimating one in terms of the other over a short range and I congratulate him for the effort. He's fairly close....but again over a short range.
Well.....just tell Mr Denton there is no equation. It’s not mine. Jerry
jwall- *** 3100 guy***
A Flat Trajectory is Never a Handicap
Speed is Trajectory's Friend !!
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Joined: May 2004
Posts: 56,194 Likes: 18
Campfire Kahuna
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Campfire Kahuna
Joined: May 2004
Posts: 56,194 Likes: 18 |
I been killin' pigs with 35 fpe? How is that possible? What are you using?..... Contender carbine, .22 short match chamber, CB shorts.
I am..........disturbed.
Concerning the difference between man and the jackass: some observers hold that there isn't any. But this wrongs the jackass. -Twain
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Joined: Nov 2008
Posts: 2,081 Likes: 1
Campfire Regular
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Campfire Regular
Joined: Nov 2008
Posts: 2,081 Likes: 1 |
Just to be a nit picker...... The divisor 450,240 was change back in the late 60's or early 70's to 450,400. Apparently a group of physicists determined the results of using the earlier number didn't quite line up with some newer or more complete observations. Or so I was told a physics professor in college.. He probably owes you a refund on at least part of your tuition. There is no one person, entity, or group who decides on the value of that constant,-- it is the combination of two other numbers, one of which is well defined and the other is pretty well defined, sorta. Kinetic energy is 1/2 m v^2. To get it in ft-lbs, you have to divide by 7000 to convert grains to pounds, and you have to divide by the acceleration due to gravity to get from slugs to foots. Standard gravity is about 32.17405 ft/sec^2, although it actually varies from place to place. So, 2 x 7000 x 32.17405 = 450,436.7 But, feel free to use anything close that you can remember. As noted, it doesn't change the result very much. But if you remember what the number is and why it is, then you can easily get the exact number anytime you want it. Enjoy, You are quite correct. The conversation with him was at his loading bench and we were discussing the various formulas for finding FPE. I mentioned that I had been using the 450240 number when he stated the more accurate formula as being 450400. He went on to explain in much greater detail on the math using, iirc, in very similar details as you mentioned and the reasoning for the change in formula which I have long since forgotten. His final comments on the issue was to simply to round it off to 450400---it was more than close enough for the purposes at hand and that if anyone thought FPE was an accurate measure of killing/stopping power that they needed to get a hell of a lot more real world experience.
~Molɔ̀ːn Labé Skýla~
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Joined: Dec 2004
Posts: 3,639
Campfire Tracker
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Campfire Tracker
Joined: Dec 2004
Posts: 3,639 |
I been killin' pigs with 35 fpe? How is that possible? What are you using?..... Contender carbine, .22 short match chamber, CB shorts. I salute you sir.....you're a better hog killer than me.....
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Joined: Mar 2006
Posts: 20,940 Likes: 3
Campfire Ranger
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Campfire Ranger
Joined: Mar 2006
Posts: 20,940 Likes: 3 |
A foot pound is the amount of energy required to lift a pound by one foot.
Your 2000 foot pound load has enough energy to move a ton upward by one foot. Somebody is going to ask why the 200 pound deer didn't fly ten feet. 200 lb Deer??!! Where?? Certainly not in Texas. I lift several pounds “per foot” with every step.
By the way, in case you missed it, Jeremiah was a bullfrog.
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Joined: May 2004
Posts: 56,194 Likes: 18
Campfire Kahuna
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Campfire Kahuna
Joined: May 2004
Posts: 56,194 Likes: 18 |
-blush-
Not that tough. Cover is dense, shots very close. Little bit of camo and move like smoke is all it takes.
I am..........disturbed.
Concerning the difference between man and the jackass: some observers hold that there isn't any. But this wrongs the jackass. -Twain
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Joined: Sep 2015
Posts: 975
Campfire Regular
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Campfire Regular
Joined: Sep 2015
Posts: 975 |
Using a different way to calculate ballistic energy that also considers diameter into the mix (diameter is what is obtuse to any bullet's direction of travel, so the larger diameter the bullet the more tissue it's striking and moving out of it's way) is to multiply diameter by weight by velocity at impact and divide by 7000 (7000 is used because we enter our weight in grains and one grain is 1/7000 of a pound)
So .224 X 55 X 3700 FPS = divided by 7000 = 6.512
......
That is a whole lot closer to the real world.
0.224 x 55 x 3700 / 7000 = 6.512 0.355 x 147 x 990 / 7000 = 7.380And today I learned a subsonic 9mm load is a more effective round than a .22-250!
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