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Thread: Interesting trivia / fact regarding AR barrel life...

  1. #11
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    I believe MarkM's sig line is appropriate for this thread!

  2. #12
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    Quote Originally Posted by gfelber View Post
    a = 1028700 m/s^2 or 1.03 * 10^6 m/s^2
    EDIT - REMARK: This assumes constant acceleration in the barrel which is probably a simplification
    Even if it is... that is 104,898.207g

    Another eye opener.

    BTW Your math is good. My math is easier. If we have delta v on given distance with constant acceleration then average v=v0-dv/2 Then with known distance we get time. Gives same result at the end. (I had always tendency to oversimplify, that is why they kicked me out from Physics at University)

    BTW2 But we know, we do not have constant acceleration due to changing pressure curve that changes force applied.
    Last edited by montrala; 12-14-11 at 19:45.
    Montrala

    I'm sponsored competition shooter representing Heckler&Koch, Kahles, Hornady and Typhoon Defence brands in Poland, so I can be biased

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  3. #13
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    Quote Originally Posted by gfelber View Post
    Someone might want to check my math as I did this quickly. The "x^2" means x squared.

    Given:

    v(initial) = 0 m/s
    v(final) = 914.4 m/s (3000 fps)
    d = 0.4064 m (16")
    a = ?
    t= ?

    v(final)^2 = v(initial)^2 + 2*a*d
    (914.4 m/s)^2 = (0 m/s)^2 + 2*a*(0.4064 m)
    836127.36 m^2/s^2 = (0.8128 m)*a
    (836127.36 m^2/s^2)/(0.8128 m)=a
    a = 1028700 m/s^2 or 1.03 * 10^6 m/s^2

    v(final) = v(initial) + a*t
    (914.4 m/s) = (0 m/s) + (1028700 m/s^2)*t
    (914.4 m/s)/(1028700 m/s^2)=t
    t = .0009 s

    10,000 rounds = 9 seconds

    EDIT - REMARK: This assumes constant acceleration in the barrel which is probably a simplification
    Not bad for a napkin calculation.



    According to this, the real answer is .0008s.
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  4. #14
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    Now THIS is my kinda physics experiment!!!
    -VERITAS VINCIT-

  5. #15
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    Quote Originally Posted by Moltke View Post
    ^^Debbie Downer over here with real facts.
    Lol.

    That is pretty crazy to think about it like that
    Quote Originally Posted by Split66 View Post
    I wouldnt listen to BCMjunkie. His brown camo clashes like hell with his surroundings. His surroundings are obviously pinkish and lacey and have big hooties.

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  6. #16
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    What the hell are you guys typing?!?! I'm pretty sure whatever it is, it's violating the forum rules for geekness...


  7. #17
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    Quote Originally Posted by gfelber View Post
    Someone might want to check my math as I did this quickly. The "x^2" means x squared.

    Given:

    v(initial) = 0 m/s
    v(final) = 914.4 m/s (3000 fps)
    d = 0.4064 m (16")
    a = ?
    t= ?

    v(final)^2 = v(initial)^2 + 2*a*d
    (914.4 m/s)^2 = (0 m/s)^2 + 2*a*(0.4064 m)
    836127.36 m^2/s^2 = (0.8128 m)*a
    (836127.36 m^2/s^2)/(0.8128 m)=a
    a = 1028700 m/s^2 or 1.03 * 10^6 m/s^2

    v(final) = v(initial) + a*t
    (914.4 m/s) = (0 m/s) + (1028700 m/s^2)*t
    (914.4 m/s)/(1028700 m/s^2)=t
    t = .0009 s

    10,000 rounds = 9 seconds

    EDIT - REMARK: This assumes constant acceleration in the barrel which is probably a simplification
    I'm getting the feeling you're into chemistry or bio-chemistry along with guns, bullits, n' stuff!?
    Last edited by MikeCLeonard; 12-14-11 at 21:49.

  8. #18
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    Ugghhh I just finished the last final exam of my college senior year today and I come to the forum for a little relaxation and light reading...and I see this

  9. #19
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    Wow...Though isn't the bullet accelerating exponentially during that trip, so the dwell time is slightly longer than that?

  10. #20
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    Quote Originally Posted by gfelber View Post
    Someone might want to check my math as I did this quickly. The "x^2" means x squared.

    Given:

    v(initial) = 0 m/s
    v(final) = 914.4 m/s (3000 fps)
    d = 0.4064 m (16")
    a = ?
    t= ?

    v(final)^2 = v(initial)^2 + 2*a*d
    (914.4 m/s)^2 = (0 m/s)^2 + 2*a*(0.4064 m)
    836127.36 m^2/s^2 = (0.8128 m)*a
    (836127.36 m^2/s^2)/(0.8128 m)=a
    a = 1028700 m/s^2 or 1.03 * 10^6 m/s^2

    v(final) = v(initial) + a*t
    (914.4 m/s) = (0 m/s) + (1028700 m/s^2)*t
    (914.4 m/s)/(1028700 m/s^2)=t
    t = .0009 s

    10,000 rounds = 9 seconds

    EDIT - REMARK: This assumes constant acceleration in the barrel which is probably a simplification
    Thank you, I needed to be reminded about my weak math skills

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