Question for Cast Bullet Designers

[Maven]

Suppose I want to make a 6.5mm (for the Swe. Mau.) version of Lyman #311291. Just for the sake of argument, let's also suppose that the alloy will be Lyman #2 and that the the ballistic coefficient for -291 is .202 and weighs 169gr. (the last 2 figs. are from Lyman's "CB Handbk., 3rd Ed."). Will a CAD program allow you to design a 6.5mm version of #311291, using Ly. #2 alloy, that has:

the same ballistic coefficient?

the same sectional density?

the same length as -291 as well?

I've been curious about this of late and am anxious to learn what you think. Thanks in advance for any assistance you can offer!

[45 2.1]

Suppose I want to make a 6.5mm (for the Swe. Mau.) version of Lyman #311291. Just for the sake of argument, let's also suppose that the alloy will be Lyman #2 and that the the ballistic coefficient for -291 is .202 and weighs 169gr. (the last 2 figs. are from Lyman's "CB Handbk., 3rd Ed."). Will a CAD program allow you to design a 6.5mm version of #311291, using Ly. #2 alloy, that has:

the same ballistic coefficient? BC will be higher

the same sectional density? No

the same length as -291 as well? Yes, but it will weigh about 135 to 140 gr.

I've been curious about this of late and am anxious to learn what you think. Thanks in advance for any assistance you can offer!

Cad allows you to draw the boolit and fit it properly to a lead throat slug, it doesn't think for you at all. Nose form, length, velocity, weight influence most of the factors you mention. You would be much better off learning to balance the boolit out and fit it properly. You and most of the others here (the BPCR guys excepted) don't shoot a cast boolit far enough to make use of BC and sectional density. You do ask some interesting questions though.