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Thread: light loads vs. heavy loads, re: bullet grain question

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    Question light loads vs. heavy loads, re: bullet grain question

    What does bullet weight, grain, have to do with light loads and heavy loads? Light loads referring to the kick, or a mild load. Take the 9mm 115 gr vs. 124 gr, standard pressure factory fmj. The 115 gr bullet is smaller, lighter, so do they use less powder and / or add filler, because wouldn't you have more room for powder since the bullet is smaller that say the 124 gr bullet?

    Or take the .44 Rem. Magnum. It seems that the heavier bullets, 300 gr, are reported to have more kick, penetration, than the lighter loads.

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    It's a matter of internal ballistics.

    No factory ammunition that I know of uses a filler to displace space within the loaded cartridge.

    You're questions about 115/124 grain 9mm vs. 300 grain .44 magnum are apples and oranges. Most likely, you won't feel much difference in recoil between 115 and 124 grain factory 9mm loads. You will feel a difference if those same weight bullets are loaded to +P pressure. Regarding the penetration part of your question, that's simple physics of the mass and velocity of the mass. More mass will penetrate much more than lighter mass at the same velocities.

    If I were to reload a standard .223 cartridge with a 55 grain fmj and 22.0 grains of powder, that would be a slightly lighter (softer felt recoil) load and is what my 10 year old daughter loads for herself (under my supervision).

    My standard load for myself is 25.0 grains of the same powder in the same case with the same 55 grain fmj bullet. It is a significantly stouter (stronger felt recoil) load.

    Recoil is a factor of charge weight, burn rate, bullet weight and weapon weight. The more powder and the heavier the bullet, the more recoil you'll feel. A quick google search for internal ballistics and felt recoil will reveal hours of reading enjoyment if you're so inclined.
    Last edited by hayes; 11-03-09 at 16:53.

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    Quote Originally Posted by f.2 View Post
    What does bullet weight, grain, have to do with light loads and heavy loads? Light loads referring to the kick, or a mild load. Take the 9mm 115 gr vs. 124 gr, standard pressure factory fmj. The 115 gr bullet is smaller, lighter, so do they use less powder and / or add filler, because wouldn't you have more room for powder since the bullet is smaller that say the 124 gr bullet?
    It all depends on the powder etc. Often lighter grain bullets have more powder. Has to do with the pressure curve, peak pressure, etc. More initial case room for expansion and lighter/smaller bullet means less pressure spike etc in many cases.
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    Quote Originally Posted by eguns-com View Post
    It all depends on the powder etc. Often lighter grain bullets have more powder. Has to do with the pressure curve, peak pressure, etc. More initial case room for expansion and lighter/smaller bullet means less pressure spike etc in many cases.
    That makes sense, thanks.

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    Quote Originally Posted by eguns-com View Post
    IOften lighter grain bullets have more powder...
    Virtually always, right?

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    Quote Originally Posted by Bimmer View Post
    Virtually always, right?
    Probably. I have really not researched more than just noticing that it is usually that way. So don't quote me. But it is very often the case. May depend on a particular powder/case combo etc.
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    Quote Originally Posted by eguns-com View Post
    Probably. I have really not researched more than just noticing that it is usually that way. So don't quote me. But it is very often the case. May depend on a particular powder/case combo etc.
    I don't pretend to know anything, but I reload, and I've seen enough load data tables to say that "lighter bullet/more powder" is virtually universal.

    The only exception that I can think of is switching from jacketed to lead bullets (which reduces the powder charge significantly). So, for .40 for example, a load for a 180gr. jacketed bullet might be more powder than a 155gr. lead bullet...

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