Ogive question

[areaone]

I notice in the Berger Manual that they refer to ogive in their bullet reference chart i.e 7.5, 8, 12, etc. What exactly does this mean.

 

[rocketron]

if it's anything like a rocket nose cone it has to do with the shape and length of the ogive.

 

[Lapua40X]

Those numbers quantify how secant an ogive is.

This explains it:

http://www.accurateshooter.com/ballistics/tangent-vs-secant-vs-hybrid-ogive-bullets/

 

[areaone]

Whoa, above my pay grade, but I think i get it, enuff for what I will do with those numbers. Thanks.

 

[M-61]

Simplified version: Think of the ogive (the curved portion of the bullet) as a portion of a circle. Now draw the rest of the circle. Measure the diameter of that circle. For the sake of discussion say it's a 30 caliber bullet and the "imaginary" circle is 3.08" in diameter. Divide the diameter of the circle by the diameter of the bullet and you get the shape of the ogive in calibers. 3.08 / .308 = 10 ogive. Seven ogive rather blunt bullets make a small circle while 17 ogives are longer and pointier and make a great big one.

Thanks for that understandable answer,Dave. Now if I have this right you'd start with the ogive and then work backwards to arrive at a 'number which would tell you whether a particular bullet indeed you have, has a pointier or blunt shape. What I mean is that just given the numbers ( without seeing the bullet) you can get an idea of what you should be looking at?