Thanks to Ray I have another challenge.
I was wandering if these look the same.
They look different in person but how much I don’t know. The one on the left looks like it has the larger ogive but in the picture It doesn’t.
What is the smallest & largest ogive?
I have always been interested in the shape of the bullets, it is easily overlooked.
Thanks to Ray I have another challenge.
Remember, in my post about ogives I said it wasn’t quite as simple as I described. When a bullet maker designs his bullet it involves more than simply drawing a radius tangental to the cylinder. If you want to look into the complexities you can find a lot of information by googling bullet ogives. The Corbin sites (bullet makers) and the Lilja sites (rifle barrel maker) are especially good ones.
lifelong - the smallest ogive for all practical purposes is .5 which is a round ball. The largest, for practical bullet purposes is around 14 or 15. That results in a very-low or ultra-low drag shape (vld & uld).
wikipedia gives a pretty good example.
The dark background makes it impossible for me to discern the bullets’ shapes.
Just out of curiosity, what are the two rounds in the photo?
We’re “oh-jive” talkin’ now…
By popular demand, here’s a rendering of (3) different 7.62 ogive profiles. No waranty expressed or implied…
Only have a “10 ogive” example loose at hand so the “7” and “13” may be a bit different for real. The “7” is a tangent ogive and the “10” and “13” are secant ogives. Complete with deluxe cyber-wood display stand…
Great job. Better than a photo.
What does a cyber tree look like?
Around here “cyber-trees” are also called “Franken-pines”. Strange looking things with communications equipment typically found in their upper parts. Play hell with a chain saw’s sharp but make for darn good fence posts if you can get one down. Bees seem to like nesting in them as every one I’ve dropped buzzed like crazy when it hit the ground.
[quote=“stanc”]The dark background makes it impossible for me to discern the bullets’ shapes.
Just out of curiosity, what are the two rounds in the photo?[/quote]
The left is a 8 x 57 and the right is a .308 Dummy
I have full shots of them on My new collection post.
I will work on getting a better background.
Dave!!! I’m getting a real good laugh from your Cyber tree. Thanks for the info on the bees. I’ll bet they sting like crazy too!!
Just for Rick I went and did a photo rendering with a “dramatic cameo effect”. It also got rid of the ugly notches on the radii.
I hereby nominate Mr. DaveE our ohfishul IAA computer graphics drawer guy. Do I hear a second?
[quote=“DaveE”]Just for Rick I went and did a photo rendering with a “dramatic cameo effect”. It also got rid of the ugly notches on the radii.
The composite core Cetme CSP-003 bullet in 7,62 x 51 (developed in Spain and in service until adoption of the Nato round) has a profile very similar to your 13 bullet, but in the spanish one the ogive curve begins from the crimping cannelure up (I mean, no cylindrical portion above the cannelure).
The “10 ogive” is real to measurements from an example but the “7” and “13” I had to guess at a little as I was only referencing the photo Ray posted in the other thread that started the ogive discussion. The geometry would work fine bringing the start of the ogive profile down to the cannelure. Ray’s example may be just like the Spanish bullet you mention but I can’t tell too well from the picture with my aging eyes.
The CETME bullets probably have a tangent ogive with a very big radius. Or maybe not. ;)
I think we’re seeing the start of a new collecting field. Virtual Cartridges. If Dave can start drawing them we can get a head start on those guys who aren’t on the Forum.
Does the US 7.62mm M80 Ball projectile have a secant ogive?
Yes, the M80 bullet is a 10 ogive. Dave’s drawing is a very good representation. The M59 bullet was a 10 also. Many bullets with an ogive of more than 7 will have a secant ogive. The secant improves the ballistic coefficient a little and also reduces the bearing length without ending up with a bullet that is overly long. It’s an attempt at fooling Mother Nature, although she can’t be fooled and we’re really only fooling ourselves thinking we can.
If possible I’d like to commission several digital-art ammo pieces as teaching aids for use at my agency. My photography skills are OK and getting better, but drawing stuff on a whiteboard SUCKS compared to the effect I could get by using renderings like yours in a presentation. This will also help with presentations where people freak if bring anything resembling live ammo (courtrooms, Hunter’s Ed at the local high school, etc…funny how they don’t freak much about the loaded gun on my hip?).
PM me with cost/logistics, and I’ll send you the individual rounds/items I need rendered.