Mould Design & Meplat Percentage

[insanelupus]

In conjunction with my question on the 280 grain .44 Moulds, I was playing around with the design program on Mountain Moulds' website.

Is there anywhere I can go for a treatise on the beneifts and drawbacks on bullet shape/design such as; Tagential Ogive, Bore Riding Tagential Ogive, Secant, Bore Riding Secant, etc., etc. Additionally I would like to learn what specifically differentiates one design from the other.

Second, would anyone happen to have a good guestimate (or perhaps memorized the measurement) for the meplat percentage of the Lman 429421, 250 grain PB Keith desing, as well as the Lee 432-310 GC WFN design? I'm not able to take those measurements for the time being and was curious. Thank you.

[Glen]

70-73% meplat seems to work best in terms of bullet stability and wound channel generation. The 429421 has a meplat diameter of about 65%. For his later bullet designs Elmer Keith moved to 70-73%.

As for the ogive shape, you can answer your own question by designing the bullets and letting the MM software draw pictures of the ogive for you.

[leftiye]

Secant ogive allows a more streamlined nose shape (as contrasted with a blunter profile with a tangent ogive).

[Dale53]

The Lee C430-310-RF has a meplat about 81%.

Dale53

[GLynn41]

Ask Dan he will normally be glad to answer your questions