David Tubb introduces a new DTAC 115gr 6mm bullet with Noseringtm

[243Mendoza]

Indeed it will at subsonic flow speeds.

...
But the rules change for supersonic flow, and I'm not sure what benefits of the nosering would accrue at supersonic flow where it would likely be tucked in behind a shock wave cone.
..

The flow over a cut would be similar to flow over a crimp or small cavity: weak expansion and shock waves i.e. more drag.

 

[sparker]

I believe the goal is to establish the boundary layer precisely on the nose for each bullet. As this effectively moves the layer back from the meplat, there is a slight decrease in BC. However due to the fact that there is a bit of variation in meplat diameters and often lack of symmetry, a more uniform BC is obtained by the ring.

 

[dcali]

Indeed it will at subsonic flow speeds.

A turbulent boundary layer is really only helpful at preventing flow separation. For example, many fighter planes have "air hockey table" like pinholes supplies with bleed air that will reduce flow separation at very high angles of attack for aggressive turns. (also why many planes have side strakes that induce vortices that pull flow over the top of the wing to also increase the angle of attack before separation.) Flow separation is why a golf ball benefits from dimples, but why dimpling an arrow would do nothing helpful.

Unless you are experiencing flow separation, the turbulent boundary induces a drag penalty at subsonic speeds that you don't need to pay.

But the rules change for supersonic flow, and I'm not sure what benefits of the nosering would accrue at supersonic flow where it would likely be tucked in behind a shock wave cone.


It seems to me that the location of the "ideal" nosering would vary a lot with speed because speed determines the cone angle of the shockwave and where it would be relative to ogive.

In any condition, the slight shift rearward in CoM would seem helpful.

I'm not convinced it will induce turbulent flow, but if it does, it will increase skin friction drag both above and below mach 1, and substantially. Bob McCoy (and others) did a bunch of work quantifying how that works out, and built it into McDrag.

 

[Brians356]

I'm not convinced it will induce turbulent flow, but if it does, it will increase skin friction drag both above and below mach 1, and substantially. Bob McCoy (and others) did a bunch of work quantifying how that works out, and built it into McDrag.

Would we be able to see turbulent flow in one of these Schlieren technique videos?

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[dcali]

Would we be able to see turbulent flow in one of these Schlieren technique videos?

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I would think so. McCoy basically said you have to look at spark shadowgraphs to see where it's going turbulent, but that for small arms bullets, it's typically at the back end of the nose. Note that we're talking about the air that is in contact with the bearing surface, ogive, and boattail. By the time it hits the boattail, you can clearly see it's turbulent. But it's harder to tell how far up the bullet is laminar- maybe you can zoom in and get some idea.

I bet the Smarter Every Day guy could sort it out - I would love to see him shoot some of Tubb's bullets to see what, if anything, the ring does. My uninformed gut is says it will either do nothing, or make things worse. But who knows. Maybe Tubb could send him some.

 

[dcali]

This isn't a bullet obviously, but it shows the transition from laminar to turbulent flow pretty well. The closer that transition is to the meplat, the higher the drag will be.

 

[Romulus]

I didn't read all the posts like I usually do, but to keep this concise:

- I've seen Oehler 88 data on these nose-rings vs standard bullets and they do increase BC Consistency or reduce "BC SD" which no one really considers as a variable in their long range shooting or vertical. Of course this is part of vertical dispersion and the NR are a simple way to get this variable mitigated. This will shrink your groupings at range.
- the terminal expansion is just another benefit IMO.
- Tools for other calibers and end-user will be available soon enough.
- some bullet designs will see nearly zero BC reduction but some will lose a small %. I don't think you will be able to predict this or get an index of end-effects, but the BC Standardization should be worth any small % BC loss for any target discipline. Your Elevation and Windage should be more standardized and predictable. I have my own thoughts on what designs will see % drop and which ones won't but I don't have the time, tech, or wallet to test it. Time will tell.
- there are more expensive ways to achieve this same result.
- Great and simple tech.

I'd use it as a competitive advantage as soon as it's available before the masses get aware of it.

 

[EdHarley]

No, that's the base of the new version of the 115 DTAC taken from David's website.

This is the old one, hence my confusion:

 

[EdHarley]

 

[243Mendoza]

Would we be able to see turbulent flow in one of these Schlieren technique videos?

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[Indianhead15613]

Marketing 101 for those easily swayed.

Where is the proof of expansion on game or accuracy or bc or whatever else is being claimed here?

Well I can tell you from experience that the nose ring bullets shoot exceptionally well and expansion is the real deal.......

 

[Brians356]

Well I can tell you from experience that the nose ring bullets shoot exceptionally well and expansion is the real deal.......

When it comes to David Tubb's word, prove him wrong.
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[Jerry NM]

I have a new unopened box of 500 of David Tubbs .243-115 gr RBT Rebated 1000 yd TBN Coated bullets that I have gotten too old to shoot. I would sell them for $120 plus actual shipping cost. jspurlin1@yahoo.com.

 

[Hoot]

An excellent deal!

 

[davidjoe]

I have a new unopened box of 500 of David Tubbs .243-115 gr RBT Rebated 1000 yd TBN Coated bullets that I have gotten too old to shoot. I would sell them for $120 plus actual shipping cost. jspurlin1@yahoo.com.

I’ll buy them, Jerry.

PM me some payment details and a picture please.

 

[tthomp302]

So has anyone used these hunting? Curious because I might want to buy some for my 6gt.

 

[mr45man]

Looks like what I used to do with ball 30 06 ammo
with a dermel.
worked on ground hogs.

 

[dave@aDave]

Tubbs design seems to have been influenced by this:
https://en.wikipedia.org/wiki/Drag-reducing_aerospike

 

[JohnMill]

This goes against my nature to admit, but I think it's pretty much bang on. I prefer to be data-informed and be able to put of accepting things until I can explain them.

But some things just ARE, whether we can explain them or not.

All of the Tubb products I have purchased have performed exactly as claimed.

Me too.

 

[Ray123]

Might just buy a box to see..how deep & wide is the groove? Special thick at the tip bullet jacket? Could make a few in the lathe, grind a mini parting/ grooving tool...and groove a few 115 gr coated DTAC bullets I have...and compare performance with non groved..."ringed."