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20 Gauge compared to .357 Magnum

Discussion in 'Shotguns' started by Laserslug, Dec 17, 2010.

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  1. Laserslug

    Laserslug Member

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    The 20 gauge shotgun slug has more than triple the energy of a .357 magnum bullet. The slug goes at 1600 feet per second. The bullet goes at 1240 fps. The 20 gauge slug has a mass of 3/4 ounce (21.3 grams). A bullet from a .357 handgun has a mass of 10.26 grams (158 grains).

    Kinetic energy = 1/2 m (v squared)

    Ordinary 2 and 3/4 inch shell ... 1/2 * 21.30 * 1600 * 1600

    Magnum .357 cartridge............... 1/2 * 10.26 * 1240 * 1240

    The ratio of slug energy divided by bullet energy is 27264000 / 7887888 = 3.46

    _________________________________________________________

    But I can buy a magnum loaded 20 gauge slug with a mass of 1 ounce (28.4 grams). Here is that calculation:

    Kinetic energy = 1/2 m (v squared)

    Magnum 3 inch shell .......... 1/2 * 28.40 * 1500 * 1500

    Magnum .357 cartridge......... 1/2 * 10.26 * 1240 * 1240

    The ratio of slug energy divided by bullet energy is 31950000 / 7887888 = 4.05

    The 20 gauge magnum slug has 4 times as much kinetic energy as a .357 magnum! The recoil from a 6.5 pound shotgun feels like the recoil from a 25 ounce handgun.
     
  2. Gryffydd

    Gryffydd Member

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    Now just to clarify, what is the point you were after? That a shotgun slug has more energy than a low-end loading for a bottom end magnum handgun cartridge? I don't think anyone will be terribly surprised by that.
     
  3. ArmedBear

    ArmedBear Member

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    The point of a .357 Magnum is that you can hold it in your hand and accurately put repeated rapid-fire rounds on target.

    If you can do that a 4" handgun loaded with 20 Gauge slugs, I suppose that you should use one.
     
  4. r6j6b

    r6j6b Member

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    reading between the lines sort of - seems as though many people believe that the vaunted .357 is quite adequate for self defense, those same people believe the 20 ga is sub-par. ionno? just what I got out of the post.
     
  5. ArmedBear

    ArmedBear Member

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    Actually, if you read this forum, you will learn that a .308 is the minimum effective round for close-range home defense, and ANY handgun is underpowered. Click the link in my sig line...
     
  6. rcmodel

    rcmodel Member in memoriam

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    It is also rumored on the Internet that a 30-30 carbine won't kill a modern deer either.

    rc
     
  7. r6j6b

    r6j6b Member

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    Tis True! With the softening of the modern general public them 4 legged critters have gotten tougher and meaner! I've heard the deer routinely visit crack houses which would explain their utter fearlessness and unstoppable demeanor
     
  8. Mudinyeri

    Mudinyeri Member

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    You have to hit the "modern" deer where he is not covered by body armor. :)
     
  9. Laserslug

    Laserslug Member

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    The point is..

    The point of this comparison is a reaction to another THR shotgun thread where someone recently said that a .357 has energy equal to a 20 gauge. That was not disputed on that thread, so I started a new thread to highlight this little known fact: A 20 gauge slug is more than 3 times as powerful as the vaunted .357 magnum.

    On November 1, 2010, in a thread called "Shotgun for a woman" MS6842 said:

    "I bought this for my wife. It the remington 870 in a 20 gauge. Though she can shoot a 12 gauge she prefers the 20 gauge and likes the set up. From what I read a 20 gauge is very doable for HD as it has the same energy of that of a357*magnum."
     

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    Last edited: Dec 17, 2010
  10. OldMac

    OldMac Member

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    I can't wait for Taurus to unveil the 20ga. Supreme Court Judge Revolver before xmas with a 16" barrel. That will certainly be a popular front carry IWB piece. Perfectly concealed.
     
  11. Jason_W

    Jason_W Member

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    Either is probably more than adequate for home defense.

    The only real disadvantage to the 20 ga, IMO, is the comparatively limited selection of factory slugs and buckshot in it.

    The largest sized factory buckshot I know of for the 20 is #4.

    Still, any gremlin you hit at an across the room distance with a 20 ga slug won't be getting back up.
     
  12. Laserslug

    Laserslug Member

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    Federal sells #3 and #2 buckshot for 20 gauge. Paraklese Technology sells 00 buckshot for 20 gauge at Gunsamerica.
     
  13. Jason_W

    Jason_W Member

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    cool. I didn't know that.
     
  14. d2wing

    d2wing Member

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    Glad you informed us of the point of your post, nice to know the facts.
     
  15. Jason_W

    Jason_W Member

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    I've done some gel tests with 20 ga sluggers. They're very frangible at close range. massive cavity, though.
     
  16. withdrawn34

    withdrawn34 Member.

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    That's odd that someone would claim a 20 ga. shotgun has the same energy as a .357 magnum. Clearly, a 12 or 20 ga shotgun would dump more energy at close range. I am not sure how anyone would get any other idea.
     
  17. brianr23

    brianr23 Member

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  18. vanguard7

    vanguard7 Member

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    placement is the key to hd, a 22 mag will do fine if you know how to use it. imho. but i use a maverick 20ga for my home defence.
     
    Last edited: Dec 18, 2010
  19. Jason_W

    Jason_W Member

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    The other thing I notice about the 20 ga is the apparent lack of shorter barrels for them. Does anyone make an 18.5" barrel for any 20 ga model?
     
  20. Mp7

    Mp7 Member

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    Thx RC "modern deer" made my day :)
     
  21. ranger335v

    ranger335v Member

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    "It is also rumored on the Internet that a 30-30 carbine won't kill a modern deer either."

    And that's at the muzzle.

    Meanwhile, back at the ranch, a custom barreled .270 WSM easily kills deer it 600+ yards IF it wears a NightForce scope.

    According to the internet Elvis is alive in Atlanta. And Geo. Bush had the twin towers and Pentagon destroyed with dynamite so Halliburton could control Arab oil.
     
  22. JohnBT

    JohnBT Member

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  23. Laserslug

    Laserslug Member

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  24. 76shuvlinoff

    76shuvlinoff Member

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    load that .357 up from powder puff and run it down a 16 or 20 inch barrel.....

    lever of course
     
  25. Zoogster

    Zoogster Member

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    The comparison is lacking some important measurements.

    One of them being sectional density. Something with a diameter of .355 takes a lot less energy or momentum to penetrate the same distance as something with a diameter of .615.
    The force of the round is exerted over a greater area, requiring more to achieve the same penetration.
    Now expanding bullets can offset this somewhat, as it increases in diameter during penetration requiring yet even more energy to penetrate the same distance, but the slug can to an extent as well.
    So while the slug is certainly much more powerful, the real world results are not as dramatic as "more than triple".


    A better determination at low velocities than energy is momentum. Momentum determines how far the round goes in tissue better, as it determines how quickly it will slow down. Since at such low velocities the damaged tissue is mainly that which directly contacts the round, energy means much less.
    3/4 ounces is about 328 grains. 328 grains at 1600 FPS gives 74.97 pounds of momentum.
    158 grains at 1240 FPS gives 27.9885 pounds of momentum.
    So about 75 and 28 respectively.
    That means the slug has just 2.6775 times more pounds of momentum. It is also applying it over a greater surface area and is subject to more resistance, so requires more for the same amount of penetration.
    The resulting wound diameter is also going to be a little less than double.
    Assuming both rounds have adequate penetration, larger diameter certainly makes shot placement easier, and larger diameter leaks blood disproportionally faster.


    Then there is the pros and cons of long arm vs handgun.
    I don't know what original thread you are referring to, so I don't know if the context was hunting, self defense from people or animals, or other factors necessary to accurately compare the platforms and rounds in specific situations.
     
    Last edited: Dec 18, 2010
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