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Thread: Physics question

  1. #1
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    Alright I'm trying to find out the muzzle energy of a round coming out of my Kimber Ultra Carry 2.

    I use Hornady 200 or 230 grain JHP rounds. The Kimber Ultra Carry 2 has a 3 inch barrel. Can anyone help me calculate this?

    I'm trying to compare the 'stopping' power of my Kimber Ultra Carry 2, that my wife is taking to my new Glock 21sf.

    Any help would be greatly appreciated.

    Thanks

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    quentusrex wrote:
    Alright I'm trying to find out the muzzle energy of a round coming out of my Kimber Ultra Carry 2.

    I use Hornady 200 or 230 grain JHP rounds. The Kimber Ultra Carry 2 has a 3 inch barrel. Can anyone help me calculate this?
    I don't think so. I think you'll need to find someone with a chronometer and measure the muzzle velocity. Then you can calculate the muzzle energy.

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    Is there a way to get a guestimate? or something along the lines of similiar barrel length pistols?

    For the 3 inch barrel is it better to go with the lighter JHP round? something like 185 grain over the 230 grain? How much difference would there be?

    I'm not looking for accurate measures just reasonable ones.

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    I found this for the 5" barrels:

    185gr (12.0g) JHP 950ft/s (290m/s) 371ft·lbf (503J) 230gr (15g) JHP 850ft/s (260m/s) 369ft·lbf (500J) 165gr (10.7g) JHP 1,060ft/s (320m/s) 412ft·lbf (559J)

    So there is a significant increase in muzzel energy for the 5" by going to the lighter bullet. How would this translate into stopping power? I'm talking more about knock down power, knocking an attacker off his feet.

  5. #5
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    Re post of better layout for the data:

    185gr (12.0g) JHP 950ft/s (290m/s) 371ft·lbf (503J)

    230gr (15g) JHP 850ft/s (260m/s) 369ft·lbf (500J)

    165gr (10.7g) JHP 1,060ft/s (320m/s) 412ft·lbf (559J)

  6. #6
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    Might try this Bullet Kinetic Energy Calculator:
    http://www.firearmexpertwitness.com/...s/calcnrg.html

    And another:
    http://billstclair.com/energy.html

    Keep in mind that "Knockdown power" is not a real measure of bullet ballistics or force, it's mostly a Hollywood special effect. People that get hit just don't get knocked over or go flying through the air (and always into windows or some other glass..why is that?). It just doesn't happen and old Mr. Newton cringes everytime that scene is played!

    Once you've selected thethe largest caliber handgunyou're comfortable with, select an ammo that suits your needs. If you live in an apartment with thin walls, JHP would likely be a better choice. If you have feed issues with JHP, EFMJ may be an option.All that's left then is practice, practice, practice. One critical shot from a .22 is worth more than any missed .45!

    Accurate shot placement is first priority, max transfer of energy to your intended target is a close second. All else is really just personal preference based on cost and what your gun "likes".

    The force required fora bullet to knock an attacker off his feet would also knock the shooter off their feet -Physics is Physics. This FBI report quotes a study that says being shot is similarto beinghit with afastball. I read that a 130 mph fastball is approx the same energy as an 1875 fps believe a 65mph fastball is approx equal to a 900fps bullet so a 90MPH fastball would actually have more energy and a greater transferrence of energy on impact. But being hit with a baseball doesn't stop attackers, critical hits to the CNS and vital organs orbleedout are what actually stop an attack(er). In self defense, we only shoot to stop the attack, not to kill the attacker. Sometimes the latter is necessary and inevitible, but it's not the goal.

    There are MANY references to this in books and on the internet. Here's probably the definitive reference (also attached):
    http://www.firearmstactical.com/pdf/fbi-hwfe.pdf

    Here's some other interesting reading:

    http://www.chuckhawks.com/energy_transfer.htm

    http://www.firearmstactical.com/tactical.htm

    http://www.firearmstactical.com/hwfe.htm


    http://www.firearmstactical.com/wound.htm

    http://www.firearmstactical.com/afte.htm

    The only guarantee for a one-shot knockdown is a critical CNS shot placement.

    Hope this helped and Happy Reading!


    Attached Files Attached Files

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    Both my wife and I are able to handle the .45 acp very well. She will be carring my Kimber Ultra carry, and can even get 7/7 in the 4 ring from 40 feet. She asked me the question of if she ever had to use it what would happen to the BG? I couldn't fully answer that question. Atleast not in any reasonable detail.

    So, I'm on the quest to answer that question in more detail than 'a round to the center of mass will stop the BG'...

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    swillden wrote:
    quentusrex wrote:
    Alright I'm trying to find out the muzzle energy of a round coming out of my Kimber Ultra Carry 2.

    I use Hornady 200 or 230 grain JHP rounds. The Kimber Ultra Carry 2 has a 3 inch barrel. Can anyone help me calculate this?
    I don't think so. I think you'll need to find someone with a chronometer and measure the muzzle velocity. Then you can calculate the muzzle energy.
    Your wife got the better deal. I have the same Kimber and would not trade it for anything else. Smart Wife:celebrate

  9. #9
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    BobCav wrote:
    Might try this Bullet Kinetic Energy Calculator:
    http://www.firearmexpertwitness.com/...s/calcnrg.html

    And another:
    http://billstclair.com/energy.html

    Keep in mind that "Knockdown power" is not a real measure of bullet ballistics or force, it's mostly a Hollywood special effect. People that get hit just don't get knocked over or go flying through the air (and always into windows or some other glass..why is that?). It just doesn't happen and old Mr. Newton cringes everytime that scene is played!

    Once you've selected thethe largest caliber handgunyou're comfortable with, select an ammo that suits your needs. If you live in an apartment with thin walls, JHP would likely be a better choice. If you have feed issues with JHP, EFMJ may be an option.All that's left then is practice, practice, practice. One critical shot from a .22 is worth more than any missed .45!

    Accurate shot placement is first priority, max transfer of energy to your intended target is a close second. All else is really just personal preference based on cost and what your gun "likes".

    The force required fora bullet to knock an attacker off his feet would also knock the shooter off their feet -Physics is Physics. This FBI report quotes a study that says being shot is similarto beinghit with afastball. I read that a 130 mph fastball is approx the same energy as an 1875 fps believe a 65mph fastball is approx equal to a 900fps bullet so a 90MPH fastball would actually have more energy and a greater transferrence of energy on impact. But being hit with a baseball doesn't stop attackers, critical hits to the CNS and vital organs orbleedout are what actually stop an attack(er). In self defense, we only shoot to stop the attack, not to kill the attacker. Sometimes the latter is necessary and inevitible, but it's not the goal.

    There are MANY references to this in books and on the internet. Here's probably the definitive reference (also attached):
    http://www.firearmstactical.com/pdf/fbi-hwfe.pdf

    Here's some other interesting reading:

    http://www.chuckhawks.com/energy_transfer.htm

    http://www.firearmstactical.com/tactical.htm

    http://www.firearmstactical.com/hwfe.htm


    http://www.firearmstactical.com/wound.htm

    http://www.firearmstactical.com/afte.htm

    The only guarantee for a one-shot knockdown is a critical CNS shot placement.

    Hope this helped and Happy Reading!

    I always enjoy your responses. Thanks for taking the time.

    Dave


  10. #10
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    BobCav wrote:
    Might try this Bullet Kinetic Energy Calculator:
    http://www.firearmexpertwitness.com/...s/calcnrg.html

    And another:
    http://billstclair.com/energy.html

    Keep in mind that "Knockdown power" is not a real measure of bullet ballistics or force, it's mostly a Hollywood special effect. People that get hit just don't get knocked over or go flying through the air (and always into windows or some other glass..why is that?). It just doesn't happen and old Mr. Newton cringes everytime that scene is played!

    Once you've selected thethe largest caliber handgunyou're comfortable with, select an ammo that suits your needs. If you live in an apartment with thin walls, JHP would likely be a better choice. If you have feed issues with JHP, EFMJ may be an option.All that's left then is practice, practice, practice. One critical shot from a .22 is worth more than any missed .45!

    Accurate shot placement is first priority, max transfer of energy to your intended target is a close second. All else is really just personal preference based on cost and what your gun "likes".

    The force required fora bullet to knock an attacker off his feet would also knock the shooter off their feet -Physics is Physics. This FBI report quotes a study that says being shot is similarto beinghit with afastball. I read that a 130 mph fastball is approx the same energy as an 1875 fps believe a 65mph fastball is approx equal to a 900fps bullet so a 90MPH fastball would actually have more energy and a greater transferrence of energy on impact. But being hit with a baseball doesn't stop attackers, critical hits to the CNS and vital organs orbleedout are what actually stop an attack(er). In self defense, we only shoot to stop the attack, not to kill the attacker. Sometimes the latter is necessary and inevitible, but it's not the goal.

    There are MANY references to this in books and on the internet. Here's probably the definitive reference (also attached):
    http://www.firearmstactical.com/pdf/fbi-hwfe.pdf

    Here's some other interesting reading:

    http://www.chuckhawks.com/energy_transfer.htm

    http://www.firearmstactical.com/tactical.htm

    http://www.firearmstactical.com/hwfe.htm


    http://www.firearmstactical.com/wound.htm

    http://www.firearmstactical.com/afte.htm

    The only guarantee for a one-shot knockdown is a critical CNS shot placement.

    Hope this helped and Happy Reading!

    My understanding of the laws of physics is that the impact from the bullet would be equal toor less than the KICK of the handgun, depending on how far you were away from the muzzle. "For every action there is an opposite and equal reaction" Or something like that. Mythbusters did on show on this subject with great effect.

    Shock, whether physical or psychological can also slow or stop an attack.
    An Amazon best seller "MY PARENTS OPEN CARRY" http://www.myparentsopencarry.com/

    *The information contained above is not meant to be legal advice, but is solely intended as a starting point for further research. These are my opinions, if you have further questions it is advisable to seek out an attorney that is well versed in firearm law.

  11. #11
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    Yep, it would be less. Losses due to barrel friction and decelleration, etc... I missed that Mythbusters....hmmm...

    I meant to add shock also, thanks for catching that. Good point.

  12. #12
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    BobCav wrote:
    Yep, it would be less. Losses due to barrel friction and decelleration, etc... I missed that Mythbusters....hmmm...

    I meant to add shock also, thanks for catching that. Good point.
    The mythbusters did a show on the knockdown power shown in movies. It was great, they use a dead pig and blast hell out of it using all types of weapons. Of course they have to step it up for effect. You may be able to see some sceneson youtube, don't know.
    An Amazon best seller "MY PARENTS OPEN CARRY" http://www.myparentsopencarry.com/

    *The information contained above is not meant to be legal advice, but is solely intended as a starting point for further research. These are my opinions, if you have further questions it is advisable to seek out an attorney that is well versed in firearm law.

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