Why is it called a "Boattail"?

[Dave M.]

Great drag chart here.

View attachment 1565246

Good thing we don’t fire the bullets and the case goes with it….Ive never seen a less useful and more hilarious diagram.
Dave

 

[Dave M.]

I think they eventually will. Or maybe I just hope they will. About 50% of rifle bullet drag is due to the base flow problems. About 120 years of study has gone into the nose design but I'm the first knucklehead to attack the base flow with math.

Less drag means a flatter trajectory (less drop) and less wind error. IT also extends the effective range of the weapon. I estimate that I could extend the effective range of the M4 out to over 500m with a aerospike tail.

I’m sure you are the first guy to study the boat tail shape….seems like a logical assumption. I’m sure Berger and Sierra never once thought about the boat tail shape and never performed any CFD on their proposed bullet shapes. Your posts are awesome, please keep them coming, this is exactly what I need in my life right now.
Dave

That is why I'm trolling this forum. I think there is a great amount of experience here. If I can get y'all shooting these then I can use the feedback to optimize them.

send me a free box of 50 of the 6.5mm pills and I would be glad to shoot them against a similar competition bullet (although 102gr is a little light for a 6.5CM competition bullet, 140gr ELD-M pills would be more appropriate).
I can’t believe you are trying to sell a new bullet design and your website doesn’t have a single shred of comparative testing showing actual results on target. Do you just expect everyone to take your word for it??
Dave

 

[Larry Koch]

Try to keep bullet cost below .15cent. That why I make my own bullets. Now there’s brass case, and powder and the over expensive primer. Keeping the primer price below .02 cents was easy until Covid. Now it much more.

 

[dellet]

Your website touts exrensive tests in 300 Blackout. That grabs my interest.

With an exceedingly long tail, low density material in a cartridge case that is powder capacity challenged, it would seem a recipe for a low velocity, heavy for cartridge bullet, that is light for length.

A good handload with an average 150 grain billet, is roughly 2000 fps. Certain flatbase bullets will net 2200 fps in a 16” barrel.

How does this bullet compare in velocity and drop at 300 yards?
Comparing to say a 150 Berger flatbase.

What is the max length it can be loaded to?

Are basic bullet dimensions available?
Over all length and boattail would be enough.

Answer by PM if you would rather not publish some answers

 

[Bc'z]

I’m sure you are the first guy to study the boat tail shape….seems like a logical assumption. I’m sure Berger and Sierra never once thought about the boat tail shape and never performed any CFD on their proposed bullet shapes. Your posts are awesome, please keep them coming, this is exactly what I need in my life right now.
Dave

send me a free box of 50 of the 6.5mm pills and I would be glad to shoot them against a similar competition bullet (although 102gr is a little light for a 6.5CM competition bullet, 140gr ELD-M pills would be more appropriate).
I can’t believe you are trying to sell a new bullet design and your website doesn’t have a single shred of comparative testing showing actual results on target. Do you just expect everyone to take your word for it??
Dave

I'd run'm against a 108 scenar, and have complete confidence in the scenar.

 

[TTE]

That is why I'm trolling this forum. I think there is a great amount of experience here. If I can get y'all shooting these then I can use the feedback to optimize them.

Furnish a few thousand to some of the guys here and maybe you will get some feed back

 

[Ledd Slinger]

Yeah we gotta see some sort of testing evidence beside theories, charts, and talk of computer simulations. I know engineers can struggle with putting the pencil down and actually doing the work, but it’s gotta be done if you want these bullets to have a chance

I’m don’t understand why the 308 bullets would need a 1 in 8” twist unless that’s just referring to the slow velocities of the 300 BLK? A larger 308 caliber round capable of pushing your 30 cal bullets in excess of 3000 fps should be able to easily stabilize a 146gr bullet with a 1 in 12” twist.

Another thing I’m seeing that breeds caution in my mind is the really short bearing surface…The long boat tail and short bearing surface makes it appear that the fulcrum point is way too far forward. Then add the fact that they are monolithic copper, and it makes me question the stability when these are pushed from a barrel with higher velocities.

 

[Iowa Fox]

So gangster!!
ChrisCraft and beautiful wood is what comes to my mind.

That's enough to make me wish I was a kid again.

 

[6.5 forever]

Nope, no moving parts. Just a weird little curved shape in the back. I'm still using full powder loads and regular reloading gear.

Looking at the drawing it appears there is a a pointed cylinder that extends forward. Heck I don't know anything....

 

[joshb]

Why not make a bullet with a pointy ass?

 

[Dgd6mm]

Why are they called pigtails?

 

[SEM]

Why not make a bullet with a pointy ass?

LOL

 

[Ledd Slinger]

Why are they called pigtails?

Why is it called “taking” a piss when you are actually leaving it in the toilet?

So many philosophical questions that are incomprehensible by the human mind…

 

[Will Henry]

The area behind a bullet is called the wake or recirculation region. It is responsible for about 50% of the drag on a boattail.
View attachment 1565243

I don't think I have ever seen a bullet shaped like the one in figure 20. Is this a development I missed? WH

 

[jelenko]

@HappyHellfire In the other thread, that's now blissfully locked, you posted some pics of groups shot with your bullets.
You need to answer at what range those were shot. To most, maybe all, people on this forum, they looked scary big. If they were shot at 100 yards or even 200 yard, you should pack up and go back to the drawling board.

Your constant harping on bullet drop is very close to 'don't care' for most/all on this forum. Broadly [there might be some exceptions] we shoot enough of the bullets we use to know their drop.
For hunting, having a flatter trajectory would be nice, but since gravity is pulling on the bullet, the trajectory is going to be close enough to what is already being use to not make much difference.

From your responses, it seems you don't have a lot of experience shooting - is that correct? What experience do you have? Have you competed in any disciplines?

 

[6BRA]

Jlk rebated boattails were some awesome shooting bullets. Best I ever shot out of a 6.5. The design has a slight resemblance.

 

[WSnyder]

I don't think I have ever seen a bullet shaped like the one in figure 20. Is this a development I missed? WH

I don’t think that’s a real depiction of a bullet shape. It’s probably a textbook drawing made by someone attempting to show the flow that has no concept of what a real bullet was shaped like. It looks obvious to me that what they thought a “bullet” was is what we would call a “cartridge”.

 

[Just Say Moe]

Playing the devils advocate here…

Accuracy is the name of the game, not distance of trajectory. And unfortunately, regardless of boat tail design, I just don’t see how an all copper bullet will ever outshoot a good match grade lead core bullet at long range. Many have tried and failed. So unless you can figure out how to stuff some lead or other heavy metal in the aerospike bullets to give them good rotating mass at the axis, you might be fighting and uphill battle both ways to get in the game at this point.

Agreed. He needs to be on a PRC forum, not a Bench rest/accuracy forum.

 

[TTE]

I'm Dr. John Stutz and I teach ballistics to engineers and scientists.

I know BRL has done a bunch of studies on making really long boatails to reduce drag. Most of the designs are unstable unless you use a very fast twist.

I don't teach ballistics to anyone and very fast twist is undefined, but ..................... duh

 

[Fast14riot]

Why is it called a boat tail? Because the modern English language developed in a nautical based region. So much of our language comes from a naval and seafaring origin.

You seem to have gotten all hands on deck, though some are calling you a loose canon. Better touch wood and go full steam ahead back to the design bench.