Turbulent boundary layer on bullet

[furrybean]

Ive just watched the podcast from Vortex and Ian Klemm.
Really interesting and in the video Ian talks about a die that scores the jacket just forward of the meplat creating a turbulent boundary layer on the bullet.

Does anyone know anything about this die?

 

[KevinThomas]

Forward of the meplat would be, literally, in front of the bullet.

 

[jamesh]

David Tubb talks about it in this youtube video.

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[furrybean]

Very interesting, or is it a solution to something that’s not a problem

 

[rardoin]

Very interesting, or is it a solution to something that’s not a problem

Now that's the $64,000,000 question!

 

[SAPenguin]

i thought the main idea behind this was to "smooth" the transition from supersonic to subsonic flight. Meaning its more for the ELR guys.

 

[FeMan]

Smooth doesn't always have the lowest drag coefficient. Golf balls are dimpled to create a turbulent boundary layer, reduce drag and make them go farther. As I recall from fluids in college (many years ago.....), what surface type has the lowest drag depends on velocity, shape and perhaps other things. I reserve the right to be amazed later, but I wouldn't expect it to make a consistent, overall improvement in bc over the velocity ranges they see in long range shooting. If they do improve bc I would think it would be over a relatively narrow velocity range. And then, the surface changes could decrease the bc over the rest of the range. Getting a net-positive gain seems unlikely to me. But as I said, I reserve the right to be amazed........

 

[SAPenguin]

I think the "nose ring"drops overall BC, but gives some consistency in the transition to subsonic..a trade off.

 

[ppaul]

What I'm hearing Mr. Tubb say is that there will be more consistency to a given lot of bullets. He also states that groups can be cut in half and that you can see the effect at even a 100 yards.

 

[Zero333]

I'm gonna wait a handful of years to hear others experience with this idea before I decide to try it for myself.

 

[Capt. Oblivious]

What I'm hearing Mr. Tubb say is that there will be more consistency to a given lot of bullets. He also states that groups can be cut in half and that you can see the effect at even a 100 yards.

You hard core BR guys are going to be measuring groups in the -

 

[Park ranger]

My el cheapo dies do this anyways.

 

[Cloudrepair]

My el cheapo dies do this anyways.

I had a set doing that before lmao

 

[Jefferson]

Smooth doesn't always have the lowest drag coefficient. Golf balls are dimpled to create a turbulent boundary layer, reduce drag and make them go farther. As I recall from fluids in college (many years ago.....), what surface type has the lowest drag depends on velocity, shape and perhaps other things. I reserve the right to be amazed later, but I wouldn't expect it to make a consistent, overall improvement in bc over the velocity ranges they see in long range shooting. If they do improve bc I would think it would be over a relatively narrow velocity range. And then, the surface changes could decrease the bc over the rest of the range. Getting a net-positive gain seems unlikely to me. But as I said, I reserve the right to be amazed........

had some Bart’s ultra that sat in the boxes in a very heavy gun safe for a decade in the basement about 40 feet from a water sistrin

when opened they were mottled and sold them for a loss

they were,manic bullets. just like the golf ball as a car wind tunnel guy told me it broke up the air

 

[fotohunt]

Dang Park Ranger you beat me to it. No wonder my ammo shoots so good. My Lee loader has done this forever.