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Thread: Lead bullet pressures are greater than jacket bullet pressures of the same weight

  1. #1
    Boolit Buddy 10mmShooter's Avatar
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    Exclamation Lead bullet pressures are greater than jacket bullet pressures of the same weight

    Here is an interesting tidbit...I would have assumed the opposite.

    Here is a quote off the Western Powders blog from their ballistics labs:


    http://blog.westernpowders.com/2014/...allistics-lab/

    Lead Bullet Pressure

    Actually it is a general question: All things being equal do lead bullets generate more pressure than jacketed bullets?

    Yes, they do. It all comes down to the frictional co-efficient. Gilding metals like copper slide more readily than lead does on a steel surface. You can write your name on a piece of paper using a lead bullet much more readily than you can with a copper one. This tendency to smear, which is why it leaves a track on paper is also why it tends to grab the barrel more quickly and increase pressures. Using jacketed bullet data with a lead bullet of the same weight will result in higher pressures, everything else being equal.
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    It may sound like common knowledge, UN arguable. I don't think like that and your not taking BOOLIT lube in to consideration in the equation. I'm going against the experts on this one and could be dead wrong.

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    {shaking head in disgust}

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    I know one thing most of my boolits don't leave any lead smeared inside the barrel EVER, some for years...The other thing, most of my guns have to be cleaned after using jacketed bullets eventually. (if I used a jacketed bullet)

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    I may well be wrong and it wouldn't be the first time. If leaving a lead smear on paper shows it has a higher coefficient of friction, then the graphite in a pencil must really be high! Also try pushing a jacketed bullet through a barrel and compare that to a lead one.
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    Quote Originally Posted by 10mmShooter View Post
    Here is an interesting tidbit...I would have assumed the opposite.
    Here is a quote off the Western Powders blog from their ballistics labs:
    http://blog.westernpowders.com/2014/...allistics-lab/
    Using jacketed bullet data with a lead bullet of the same weight will result in higher pressures, everything else being equal.
    Quickload will show you what the real differences are. Western Powders has it backwards.
    Last edited by Dutch4122; 04-15-2014 at 07:10 PM.
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    With all the ability to measure pressure these days. ........

    Larry Gibson

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    In my experience all else being equal a cast lubricated boolit will give lower velocity of in the neighborhood of 150 fps depending on the type of load and cartridge.
    Since I can not accurately measure pressure but can accurately measure velocity I use velocity as an indicator of pressure.
    In my own observations lower velocity reads as lower pressure.
    Another point I would like to make is this if a jacketed bullet has less friction resistance in its passage through a barrel why then do we not use jacketed bullets to slug our barrels?

  9. #9
    Boolit Master
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    Since a cast lead lubed boolit of the same weight of a jacketed boolit with the same powder charge generally reaches a higher muzzle velocity (often 150 to 250 fps.) At least that is what I have found on my home range and chronograph. Depends on the lube I guess.

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    I can't believe that Western Powders thinks there's lead in a pencil?

    It says it's a blog, did Western Powders make that statement or someone with their head screwed on backwards.

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    That's just silly.
    The solid soft lead bullet is undoubtably the best and most satisfactory expanding bullet that has ever been designed. It invariably mushrooms perfectly, and never breaks up. With the metal base that is essential for velocities of 2000 f.s. and upwards to protect the naked base, these metal-based soft lead bullets are splendid.
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    Forget everything you know about loading jacketed bullets. This is a whole new ball game!


  12. #12
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    BULLhocky.

    Why do you think that all plain journal bearings like in every car out there are lined with LEAD alloy?
    Because it has extremely low coefficient of friction on smooth steel when properly lubricated. Lower
    than anything else or they would be using the "anything else".

    Bill
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  13. #13
    Boolit Master waco's Avatar
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    This belongs in the "silliest things you've heard" thread a few lines down.
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  14. #14
    Boolit Master
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    I think they got it bassakwards
    Hell, I was there!

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    Maybe someone should tell them.

  16. #16
    Boolit Grand Master fredj338's Avatar
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    Quote Originally Posted by 10mmShooter View Post
    Here is an interesting tidbit...I would have assumed the opposite.

    Here is a quote off the Western Powders blog from their ballistics labs:


    http://blog.westernpowders.com/2014/...allistics-lab/

    Lead Bullet Pressure

    Actually it is a general question: All things being equal do lead bullets generate more pressure than jacketed bullets?

    Yes, they do. It all comes down to the frictional co-efficient. Gilding metals like copper slide more readily than lead does on a steel surface. You can write your name on a piece of paper using a lead bullet much more readily than you can with a copper one. This tendency to smear, which is why it leaves a track on paper is also why it tends to grab the barrel more quickly and increase pressures. Using jacketed bullet data with a lead bullet of the same weight will result in higher pressures, everything else being equal.
    I have always felt this way about lead bullets. The size, better pressure seal, & higher friction raise pressures. Not a lot, but a bit higher than equiv jacketed loads. I don't believe lead in fuels is the same as pushing a lead bullet down a bbl. Until I can get a Pressure Trace setup to prove or disprove it, that is my story.
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  18. #18
    Boolit Master
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    There's a gentleman who posted above who has pressure test equipment and has done a good deal of pressure testing with cast and jacketed. He's not speculating when he signals his disagreement with the premise.

  19. #19
    Boolit Master


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    That is another case of an "expert" mouthing off about lead bullets.


    Lyman 49.

    .30-30

    170 grain jacketed
    3031 28.5 gr 36,900 CUP


    170 gr Cast
    3031 28.5 gr 32,500 CUP


    Examples are not easy to find but if you look there are plenty of them in there.

    I have never seen a case where the cast bullet produced higher pressure than jacketed.
    Last edited by williamwaco; 04-15-2014 at 09:57 PM.
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  20. #20
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    Quote Originally Posted by LynC2 View Post
    I may well be wrong and it wouldn't be the first time. If leaving a lead smear on paper shows it has a higher coefficient of friction, then the graphite in a pencil must really be high! Also try pushing a jacketed bullet through a barrel and compare that to a lead one.

    Touche'
    First reload: .22 Hornet. 1956.
    More at: http://reloadingtips.com/

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    government take care of him better take a closer look at the American Indian."
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