Ogive , what is it ?

[Metal god]

I always thought I had a good understanding of what the ogive of a bullet is . I still do but realized I don’t have it in my vocabulary to explian what it is or at least don’t know how to explain it in detail.

What’s the best , quickest and most detailed way to explain what the ogive of a bullet is to someone who has never heard of the term ?

Is it the area of the bullet where the profile of the bullet changes from the full diameter of the caliber to the tapered angle of the nose ? What’s the best way to say it ? Or should that be said backwards. It’s where the tapered angle of the nose transitions to the full diameter of the projectile ?

 

[Unclenick]

From the SAAMI glossary:

OGIVE

The curved portion of a bullet forward of the bearing surface.

 

[Metal god]

That definition would seem to indicate the ogive is not a fixed point but rather can be measured from many different points on the projectile . Example some Berger VLD have a short curved area then a long pretty flat area to the tip . While round nose bullets are pretty much curved the entire area forward of the baring surface all the way to the tip . On a round nose bullet , is the entire nose area minus the tip considered the ogive ?

 

[Don Fischer]

Way I get it is it's the first part of the bullet to touch the lands in the barrel.

 

[Gary Wells]

In the machining, inspection, quality control, & engineering sector the point where the radius begins and the full dia ends would be referred to as the tangent point. Tangent point is also the intersection point of 2 lines forming an angle.
It's been a while, better double check.

 

[Brian Pfleuger]

That definition would seem to indicate the ogive is not a fixed point

Indeed, but you will also sometimes see the word loosely used in reference to where the ogive starts, the first place back from the tip that is full caliber diameter.

rather can be measured from many different points on the projectile .

From many different points on different projectiles... only one correct point on any given projectile.

 

[gwpercle]

That definition would seem to indicate the ogive is not a fixed point but rather can be measured from many different points on the projectile . Example some Berger VLD have a short curved area then a long pretty flat area to the tip . While round nose bullets are pretty much curved the entire area forward of the baring surface all the way to the tip . On a round nose bullet , is the entire nose area minus the tip considered the ogive ?

That is correct , it is not a fixed point, it is the curved part of the bullet , forward of the bearing surface that curves to form the smaller point of the bullet.
Ogives vary in arch dimension and length .
Gary

 

[F. Guffey]

And you can turn it over to the young students, my wife has taught school for 30+ years, she would expect one of the young ones to come up with something like:

"Ogive me a home where the buffalo roam" and then there was the parent that came to see her about the pronouncing of her Childs name. The parent claimed the 'dash' was not silent.

F. Guffey

 

[Unclenick]

Example some Berger VLD have a short curved area then a long pretty flat area to the tip.

But it's not flat, it's just a much longer radius so it has less obvious curvature. That's Berger's hybrid ogive design. The first curved part is a section of tangent ogive (bearing surface tangent to the curve lengthwise) that goes on just far enough to be sure the rifling engages that part. This is used because tangent ogives self-center better in the throat than a secant ogive does. Secant ogives have a longer radius so they look flatter in profile and they have lower drag (higher BC), but when they go all the way to the shoulder at the top of the bearing surface they can introduce accuracy problems related to the bullet not centering well in the throat. The difference is a tangent ogive first finds the start of the lands at the bore diameter, while a secant ogive first finds the start of the lands at the groove diameter. The former tends to self-center better.

 

[Metal god]

Ok I'm will to except the ogive is any part of the nose of the bullet after the tip and before the diameter of the barring surface . I always thought of it as the portion closest to the diameter of the baring surface . It's funny though because my micrometer seating stems by this definition all seat off the ogive but are engaging the ogive WAY out by the tip of the bullets nowhere near the baring surface .

 

[Unclenick]

Yes. And ogive isn't just for bullets. It's an engineering geometry term and can apply to 2 dimensional shapes, too. The Wikipedia has it here. As an example, the gothic arches in church architecture that have a sharp point rather than the rounded tip of the Roman arch is called an ogive.

 

[T. O'Heir]

It's the part of the bullet/cartridge that has nothing whatever to do with the OAL.
Merriam and her dictionary says, "1a : a diagonal arch or rib across a Gothic vault
b : a pointed arch(that's a Spitzer bullet)
2 : a graph of a cumulative distribution function or a cumulative frequency distribution."
And it's 'bearing surface" not 'baring'.

 

[Unclenick]

It's the part of the bullet/cartridge that has nothing whatever to do with the OAL

The cartridge overall length terminates where the ogive does at the bullet tip. It certainly makes up part of the length that is included in the measurement, so I don't understand what you are saying.

 

[Gary Wells]

The ogive can have a tangent radius; that is, the intersection of the body of the bullet and the radius of the ogive blend together at a tangent point. This is the most common type and is typical of most bullets handloaders use. The other common type is the secant ogive.
Bullet Design–Secant vs. Tangent Ogive « Daily Bulletin
bulletin.accurateshooter.com/2007/07/283/

 

[44 AMP]

Way I get it is it's the first part of the bullet to touch the lands in the barrel.

No, the ogive never touches the barrel. The ogive is the curved/sloped/slanted/tapered part of the bullet between the leading edge of the bearing surface (the full diameter part that DOES touch the lands) and the tip (or meplat) of the bullet.

The Ogive is that entire area, and anyone using the term "measured to the ogive" is referring to measuring to a point on the ogive that THEY picked.

Which can, of course be a different spot for each person doing the picking...

 

[hounddawg]

In reality it originated as a architectural shape used to describe cathedral windows.

When I am talking reloading though I, like most everyone I know, consider it the farthest forward part of the bearing surface of the bullet where the real ogive begins. In other words the first part of the bullet to contact the throat.

 

[Unclenick]

As shown in my drawing, the intersection of bearing surface and ogive is called the shoulder. The part of the bullet that maintains contact with the floor of the grooves is the bearing surface. The part that first makes contact with the lands is the beginning (going from base to nose) of the ogive where is just starts to come away from the shoulder, but behind it the bearing surface becomes impressed into the distorted cross-section.

 

[F. Guffey]

And then there the two diameters of the bore; the .308 diameters are .300" and .308". When the rifling contacts the bullet it has to be between .300" and .308". I have never has an infatuation with 'ogive'.

F. Guffey

 

[lordmorgul]

And you can turn it over to the young students, my wife has taught school for 30+ years, she would expect one of the young ones to come up with something like:



"Ogive me a home where the buffalo roam" and then there was the parent that came to see her about the pronouncing of her Childs name. The parent claimed the 'dash' was not silent.



F. Guffey

My wife also had to be corrected that a students name “la-a” was pronounced “ladasha” not “la ah”.



Andrew - Lancaster, CA
NRA Life Member, Calguns.net contributor, CGF / SAF / CRPA / FPC / NRA-ILA contributor, USCCA member

 

[cw308]

Wouldn't touch this one with a 10 foot pole . But did learn something new " Ogive me a home where the buffalo roam" now that was funny , LOL . Thank God you didn't ask about headspace . Good luck guys.