As I understand it, an Ogive is the slanty portion of the boolit from the thickest part to the tip. (Yes slanty portion is a technical term )
But why is it important? This is eluding me.
As I understand it, an Ogive is the slanty portion of the boolit from the thickest part to the tip. (Yes slanty portion is a technical term )
But why is it important? This is eluding me.
Just knowing enough to do it, is not enough to do it right! -Taz
One reason to consider, in an auto feeding firearm the ogive can impact how well the bullet ramps into the chamber when stripped from magazine.
Ogive is the part of the slanty that is used to measure the distance to the rifling. "The bullet will be x number of thousands off the lands."
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The "ogive" is important because it's shape;
provides smooth feeding of the cartridge from magazine into chamber
determines how efficiently the bullet flies through the air (ballistic coefficient)
can determine the efficient transition of the bullet from sonic to sub-sonic
can give or promote the desired terminal effect
Larry Gibson
“Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
― Nikola Tesla
Here is a pretty good definition. https://en.wikipedia.org/wiki/Ogive
In reloading this shape may dictate the OAL of a particular cartridge in a paticular barrel. Some shapes in certain chambers may have to be seated deep to chamber or the barrel would need DougGuys work to chamber at suggested OAL .
Last edited by onelight; 06-17-2020 at 09:46 AM.
It's a combination of taper and curve. https://en.wikipedia.org/wiki/Ogive Nice little drawing of the 9mm parabellum there to illustrate, and a photo of the fuel tank on the space shuttle.
HTH!
Bill
But why so many different curves to an ogive? I have a dozen .30 cal boolits that all have a different ogive but have the same base and very close weights to each other. Pointy (sharp actually) to rounded.
OP didn't ask for definition of olive.
He asked why the ogive is important.
Larry Gibson
“Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
― Nikola Tesla
Last edited by Larry Gibson; 06-17-2020 at 01:05 PM.
Larry Gibson
“Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
― Nikola Tesla
I have recently made swaging dies for 9MM Parbellum. To my chagrin, when testing the loading with some made up dummy rounds, they stuck in the throat of my pistol. (Don't you just hate it when stuff gets stuck in your throat?)
I finally actually measured the ogive on the things...They looked good but the ogive was too short. So I went and measured out a "2" ogive. The same as the very common round nose Lee 124 gn mold. I also left the "step" in the bullet where the ogive starts. Here is a picture of the difference. The one on the left is the short ogive. Middle is the reworked ogive. The end one is the bullet from the mold.
Last edited by Traffer; 06-17-2020 at 08:48 PM.
The olgive is important when hunting. It can make the difference if the boolit will quickly mushroom, penetrate deep, if needed or just pass right through leaving minimal damage.
Ogive does affect seating depth as a side effect. Ogive also has a definite effect on feeding and function. The big reason for the ogive is its effect on the bullets Ballistic Coefficient. While not nearly as important on pistol bullets, t makes a big difference on rifle bullets compare the old round nose with the newer vld 6 and 8 ogive bullets its much higher and these bullets shoot much flatter.
These 6 and 8 ogive bullets are also much longer for a given weight meaning a faster twist may be needed for them to stabilize. A good way to see ogive is in the original 6 mm rems they would stabilize the blunt 100 grn round nose some times the spire points not the spitzers or longer pointed bullets. Ogive has a lot of effects and all need to be considered
No one has asked but ogive is pronounced Oh-JIVE. And ogive is the entire portion from full diameter to the meplat (nose).
Thanks guys! You have helped me with more knowledge.
Just knowing enough to do it, is not enough to do it right! -Taz
The ogive has some to do with bullet stability when transitioning from supersonic to subsonic but not as much as aerodynamics in flight. What does have a major influence in the transition, is if the bullet is bevel base or plain based, with plain being much more stable when breaking through the pressure bow. Whether or not the bullet has driving bands or is smooth sided has a pronounced effect, with bullets featuring driving bands being able to make the transition better. The bands cause turbulance to disperse before it reaches the base.
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |