Why is it called a "Boattail"?

[Bill Norris]

Looking at the post describing him and his education one of the listings under CLASSES TAUGHT is Senior Engineering Design (Capstone) Wondering if this is the same Capstone that Berger Bullets are under.

 

[Bc'z]

Looking at the post describing him and his education one of the listings under CLASSES TAUGHT is Senior Engineering Design (Capstone) Wondering if this is the same Capstone that Berger Bullets are under.

Ok let's think about this a lil deeper....
If it's the same Capstone, then why haven't they tested, proven, and produced the bullets in question?
Hmmmm?
Beer run, popcorn gets in my teeth.

Edited to add...
I saw a target in 1 of these fishing expedition threads, if wasn't shot at 300 yards then all this is just a waste of everyone's time and energy. IMHO
Now for that beer

 

[spclark]

Looking at the post describing him and his education one of the listings under CLASSES TAUGHT is Senior Engineering Design (Capstone) Wondering if this is the same Capstone that Berger Bullets are under.

If they're one and the same I'd have to believe the OP has had (some) contact with Brian Litz.

I for one would like to hear what Brian thinks of this 'breakthrough' technology.

 

[wedgy]

I still think English is not his first language, I’m trying to be patient and I’d gladly shoot his 6.5mm bullets up against 140 Berger hybrids or Hornady ELD-M.
I starting to think that one of the guys on this site has created the new Hellfire profile and he is laughing his ass off while we all get PUNKED. Possibly the longest April Fools Day joke in preparation for 4/1/2025??
Dave

GUFFEY !!!!!

 

[wildcat3d]

Why not make a bullet with a pointy ass?

Wait, you don't seat the pointy part in the case?

 

[1911nut]

Looking at the post describing him and his education one of the listings under CLASSES TAUGHT is Senior Engineering Design (Capstone) Wondering if this is the same Capstone that Berger Bullets are under.

Probably a university course, typically taken by seniors in their last semester, capstone.

 

[Bill Norris]

Probably a university course, typically taken by seniors in their last semester, capstone.

Yea could be but it did catch my headlights there.

 

[Richard Jones]

"Why is it called a boattail?"

You gotta call it something.......

 

[Wild Bill IV]

"Why is it called a boattail?"

You gotta call it something.......

Air Torpedoes!!!

 

[Thauglor]

Looking at the post describing him and his education one of the listings under CLASSES TAUGHT is Senior Engineering Design (Capstone) Wondering if this is the same Capstone that Berger Bullets are under.

It's called a capstone design project since it's the final project with the goal of putting all your accumulated knowledge together. Has nothing to do eith lapua/berger capstone. A lot of universities call it that

Can someone email the professor at his university email to confirm it is him? I would hate to have this guy take his name and run it through the mud here but also not surprise if it's really him. I work with a lot of researchers with phds, a lot think they know everything but I can't see how they even manage to tie their shoes

 

[Bill Norris]

It's called a capstone design project since it's the final project with the goal of putting all your accumulated knowledge together. Has nothing to do eith lapua/berger capstone. A lot of universities call it that

Can someone email the professor at his university email to confirm it is him? I would hate to have this guy take his name and run it through the mud here but also not surprise if it's really him. I work with a lot of researchers with phds, a lot think they know everything but I can't see how they even manage to tie their shoes

Thank you for the explanation Bro.

 

[Dave M.]

It's called a capstone design project since it's the final project with the goal of putting all your accumulated knowledge together. Has nothing to do eith lapua/berger capstone. A lot of universities call it that

Can someone email the professor at his university email to confirm it is him? I would hate to have this guy take his name and run it through the mud here but also not surprise if it's really him. I work with a lot of researchers with phds, a lot think they know everything but I can't see how they even manage to tie their shoes

I have already done so and waiting for a reply.
Dave

 

[dellet]

I just have one question I hope will be answered, it very simple, how are your bullets stabilized, it appears spin rate is not the main factor?

You claim stability at 1750 fps in 1/8 twist. That’s 157,500 rpm. Near max velocity in 300 Blackout.

Yet you say they can not be stabilized in a 1/10. Low end velocity for a 308 would be 2500 fps, or 180,000 rpm.

Can you please explain this, as it seems counter to what would be considered common knowledge

 

[CaptJim]

Traveling through air is just like traveling through water except the medium (air) is less dense.
Years ago I developed Schlerin backlit photos of different shaped re-entry nosecone shapes and SST (which the Brits beat us to with the Concorde) wing profiles in a wind tunnel test for the engineers and scientists to study at NASA. The different air flow patterns and resulting turbulence for the various shapes were clearly visible.
Just thought I'd share that since it was similar to what is being discussed here. We are always wanting to develop a better mouse trap (or bullet profile).
CJ

 

[HappyHellfire]

I just have one question I hope will be answered, it very simple, how are your bullets stabilized, it appears spin rate is not the main factor?

You claim stability at 1750 fps in 1/8 twist. That’s 157,500 rpm. Near max velocity in 300 Blackout.

Yet you say they can not be stabilized in a 1/10. Low end velocity for a 308 would be 2500 fps, or 180,000 rpm.

Can you please explain this, as it seems counter to what would be considered common knowledge

Spin rate is absolutely important. For the vast majority of bullets, if the bullet is stable out of the muzzle it will be stable to transonic. You can take the equation for gyroscopic stability and convert it to barrel twist.

The equation looks like:


The bigger the twist number (slower twist), the lower the stability. The overturning moment coefficient changes with muzzle velocity but changes much more slowly. It is estimated at 2.5 at Mach 2.5 and increases to around 3 at Mach 1.4.

Hope this helps!

 

[ebb]

Impressive credentials to say the least. I have on many occasions received blueprint type drawings that gave me a room size and a door schedule and upon doing the math found out that there were more doors than there was space for them in the room. That may be what we are dealing with here. Book smart real world not so smart. Nobody tests long range bullets on a 300BLK, nobody comes to Accurate shooter where some of the best LR shooters converse and talks about tested and proven bullets with data from a radar that has a 100yd max. But that may not mean his concept is wrong or the engineering is wrong. I hope he picked some shooters that can get it done and we get a truthful and accurate report. wouldn't bother me a bit to get better bullets. I hope your results impress HappyHellfire.

 

[dellet]

Spin rate is absolutely important. For the vast majority of bullets, if the bullet is stable out of the muzzle it will be stable to transonic. You can take the equation for gyroscopic stability and convert it to barrel twist.

The equation looks like:

View attachment 1565874
The bigger the twist number (slower twist), the lower the stability. The overturning moment coefficient changes with muzzle velocity but changes much more slowly. It is estimated at 2.5 at Mach 2.5 and increases to around 3 at Mach 1.4.

Hope this helps!

I think I’m missing a few of the needed inputs for that equation to work.

The real question is since twist rate is immaterial, it’s spin rate that counts, a bullet that becomes unstable, at a higher RPM and higher velocity has one of two problems. It’s either not balance gyroscopically, spin, or the center of pressure and balance is off.


A simple comparison between 1/8 at 1750 and 1/12 at 2550 would probably show on target at distance if it’s spin rate or pressure.

Or is that to simple minded

 

[Thauglor]

Spin rate is absolutely important. For the vast majority of bullets, if the bullet is stable out of the muzzle it will be stable to transonic. You can take the equation for gyroscopic stability and convert it to barrel twist.

The equation looks like:

View attachment 1565874
The bigger the twist number (slower twist), the lower the stability. The overturning moment coefficient changes with muzzle velocity but changes much more slowly. It is estimated at 2.5 at Mach 2.5 and increases to around 3 at Mach 1.4.

Hope this helps!

I just have one question I hope will be answered, it very simple, how are your bullets stabilized, it appears spin rate is not the main factor?

You claim stability at 1750 fps in 1/8 twist. That’s 157,500 rpm. Near max velocity in 300 Blackout.

Yet you say they can not be stabilized in a 1/10. Low end velocity for a 308 would be 2500 fps, or 180,000 rpm.

Can you please explain this, as it seems counter to what would be considered common knowledge

Notice how he responded to your question but didn't actually answer your question but went off on a tangential with more of his equation BS to try and appear smart.

The fact that the forum mods are letting his BS and trolling continue is a detriment and shame to this whole forum and it's users interested in real knowledge. Sad that the mods aren't doing more except deleting others posts (like mine) but leaving his. Good to know where this forum is heading

 

[Thauglor]

I think I’m missing a few of the needed inputs for that equation to work.

The real question is since twist rate is immaterial, it’s spin rate that counts, a bullet that becomes unstable, at a higher RPM and higher velocity has one of two problems. It’s either not balance gyroscopically, spin, or the center of pressure and balance is off.


A simple comparison between 1/8 at 1750 and 1/12 at 2550 would probably show on target at distance if it’s spin rate or pressure.

Or is that to simple minded

You have it correct dellet, he just doesn't answer questions when asked

 

[HappyHellfire]

I think I’m missing a few of the needed inputs for that equation to work.

The real question is since twist rate is immaterial, it’s spin rate that counts, a bullet that becomes unstable, at a higher RPM and higher velocity has one of two problems. It’s either not balance gyroscopically, spin, or the center of pressure and balance is off.


A simple comparison between 1/8 at 1750 and 1/12 at 2550 would probably show on target at distance if it’s spin rate or pressure.

Or is that to simple minded

Twist rate IS IMPORTANT! That is what the equation shows.