If bullets are designed by volume vs weight?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by royinidaho, Jan 2, 2010.

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  1. royinidaho

    royinidaho Well-Known Member

    Jan 20, 2004
    I've been doing a fair amount of hitting the books on bullet design, etc.

    I was surprised to read in more than one place that bullets are designed by volume not weight.

    I also noticed that the benchrest bullet makers don't seem to adhere so rigidly to a/the weight designation standard. 30 cal 115s being an example (30 BR)

    In our world what says the 169.5 weight 277 bullet is the cat's meow. Why not 169 or 170.1? Just as an example.

    It seems that things have evolved since the early days of the industry that the the weight has become the 'name' for a class of bullet. Other descriptive adjectives and feature are added on to further describe a bullet. (Accubond, Ballistic Tip.......)

    Just wondering...........:rolleyes:

    Are we stuck in some one else's box?
  2. Chas1

    Chas1 Well-Known Member

    Feb 15, 2009
    I'm not sure if we're stuck in someone else's box or if it's paradigm paralysis: the inability or refusal to see beyond the current models of thinking. In either case it would require significant conditions to facilitate changing system of thought. Aside from this, bullet weight is a factor...where it ranks on the list of factors I couldn't say...I'll leave that to the experts but, if it were ranked number 1 then maybe the current model is appropriate.
  3. Varminator 911

    Varminator 911 Well-Known Member

    Dec 7, 2007
    I would think that bullet makers are frequently designing a bullet to fit the factory twists. They aren't going to sell many bullets for twists faster than factory standards. That means they are limited in bullet length which equates to volume. A long range lead core bullet will be heavier than copper if they are designed for the same twist. There are a lot more weights now than 20 yrs ago. There is also a lot more demand for long, high BC bullets. But I haven't seen much change in factory twist rates, not yet anyway. I guess there are more fast twist 224 factory rifles but they are just catching up to larger calibers.

    So are they designing by bullet volume, bullet length, or to fit a certain twist rate?
  4. Mikecr

    Mikecr Well-Known Member

    Aug 10, 2003
    Sometimes I wonder if it comes down to a standard set of ratios, that bullet dies are commonly in compliance with.
    A couple AR15 platform cartridges come out, and suddenly we have more than one maker of 123gr bullets (another odd weight). Definitely not happening by chance..

    Personally, I would prefer bullet makers pick a brand standard, and hold those ratios for every cal in their lineup. That way they might afford external ballistic testing of any one of them, and the rest would accurately correlate.
    But then something else would need to happen that isn't; bullets would need to be made to, and verified to match that standard before going in each box. And by standard, I do not mean -all the same within a lot. I mean all in my box matching a declared and rigid blueprint.
    This might be an optional lot that they could charge a little more for.
    I would pay a bit more also if I did not have to point, meplat trim, and BL sort their bullets.
    Last edited: Jan 2, 2010