The 6UM

[Lawnboi]

Can someone explain the nose ring to me? And maybe how these dtacs upset?

 

[PathFinder]

Can someone explain the nose ring to me? And maybe how these dtacs upset?

The principle behind the terminal purpose of it is that it creates 1. A thinned section and 2. A stress riser in the jacket of the bullet. That is in addition to the BC deviation reducing characteristics of it.
It should allow a closed tip type match bullet to reliably upset by creating a weakness in the jacket.
Form or someone with some actual experience would have to explain the details of what actually occurs. There is some information further back in the thread.
I'm hoping to try them out on a bear here in a few weeks if everything is ready. It's a bit different from the Bergers and ELD M I'm accustomed to but the initial terminal results look pretty convincing.

 

[Ryan Avery]

Can someone explain the nose ring to me? And maybe how these dtacs upset?

I could give you the redneck run down, but I will let @Formidilosus give a more articulate answer.

 

[Formidilosus]

Can someone explain the nose ring to me? And maybe how these dtacs upset?

The DTAC is a closed nose design- there is no opening whatsoever in the tip of the bullet. The Nose Ring does two things- 1) reduces the bullets BC standard deviation; and 2) is “supposed” to create a fracture point for the tip to break off upon impact, exposing a wide open hollow point and the lead for rapid fragmentation.

This is what the bullet looks like with the tip broke off (you can see the Nosering in the pics Ryan posted)-






So ostensibly the hits point forward, the nose breaks off exposing the massive cavity, and then still point forward it fragments violently….

Well reality is funny sometimes. Sometimes it does exactly that. But, usually not. In order for the nose to break off it needs lateral pressure- I.E., sideways pressure. Pushing straight down on the nose does nothing, the moment you put any sideways angle into the pressure, the tip starts to bend/break. If we understand what things do in tissue/fluid, then it becomes obvious that in order for that tip to break off in an animal, the bullet is going to be yawing (tumbling). Even if it didn’t yaw first, the tip doesn’t come off perfectly from the front, it breaks sideways: as soon as there is drag to one side of the point forward bullet, it pulls the bullet in that direction starting the yaw, aka tumbling.


So what we have seen in some testing, and 22 or 23 animals (mostly elk) is that one of four things happens, and it’s random which ones.

1). Bullet appears to stay point forward, the nose breaks off and the bullet fragments violently. This seems to happen more with deeper nose cuts, and higher velocity impacts- 10-15%’ish of the time.

2). The bullet yaws (tumbles) 4-6 inches inside the animal, the nose breaks off, and the bullet fragments more like a Berger and other similar OTM’s. The DTAC has a thicker jacket and stays together/penetrates deeper, usually exiting elk. This seems to happen about 50% of the time.

3). The bullet yaws (tumbles) inside the animal at 4-6 inches deep, the tip breaks off but the bullet does not fragment, instead it stays together and tumbles one or two times before generally exiting.

Example of that-




4). And only seen this year with elk and 3 shots- the tip breaks off, the bullet stays point forward and expands exactly as how a bullet is “supposed” to.


Examples of that-









The key point here, is that like all bullets that rely on yawing as the mechanism for bullet upset- is variability. Not necessarily variability in “killing” or wound size created- all wounds have been very good to excellent, but in how the bullet behaves. If someone thinks that what a bullet looks like after it’s pulled out of an animal determines how well it kills, they’ll hate the DTAC NR. If, they only care how it kills, they’ll like it. A yawing bullet crushes a lot of tissue, and a rapidly fragmenting bullet creates very large wounds- they just do it differently.



The 115gr DTAC Noserings (esp. the deeper cut ones) are my preference for elk in 6mm. IIRC 16 of 18 have exited from 60 yards to 970 yards; all have created very good wounds, and all killed quickly. Even at 1,500 something FPs impact they tumbled and preformed very well.

 

[Lawnboi]

The DTAC is a closed nose design- there is no opening whatsoever in the tip of the bullet. The Nose Ring does two things- 1) reduces the bullets BC standard deviation; and 2) is “supposed” to create a fracture point for the tip to break off upon impact, exposing a wide open hollow point and the lead for rapid fragmentation.

This is what the bullet looks like with the tip broke off (you can see the Nosering in the pics Ryan posted)-

View attachment 539526

View attachment 539527


So ostensibly the hits point forward, the nose breaks off exposing the massive cavity, and then still point forward it fragments violently….

Well reality is funny sometimes. Sometimes it does exactly that. But, usually not. In order for the nose to break off it needs lateral pressure- I.E., sideways pressure. Pushing straight down on the nose does nothing, the moment you put any sideways angle into the pressure, the tip starts to bend/break. If we understand what things do in tissue/fluid, then it becomes obvious that in order for that tip to break off in an animal, the bullet is going to be yawing (tumbling). Even if it didn’t yaw first, the tip doesn’t come off perfectly from the front, it breaks sideways: as soon as there is drag to one side of the point forward bullet, it pulls the bullet in that direction starting the yaw, aka tumbling.


So what we have seen in some testing, and 22 or 23 animals (mostly elk) is that one of four things happens, and it’s random which ones.

1). Bullet appears to stay point forward, the nose breaks off and the bullet fragments violently. This seems to happen more with deeper nose cuts, and higher velocity impacts- 10-15%’ish of the time.

2). The bullet yaws (tumbles) 4-6 inches inside the animal, the nose breaks off, and the bullet fragments more like a Berger and other similar OTM’s. The DTAC has a thicker jacket and stays together/penetrates deeper, usually exiting elk. This seems to happen about 50% of the time.

3). The bullet yaws (tumbles) inside the animal at 4-6 inches deep, the tip breaks off but the bullet does not fragment, instead it stays together and tumbles one or two times before generally exiting.

Example of that-
View attachment 539530



4). And only seen this year with elk and 3 shots- the tip breaks off, the bullet stays point forward and expands exactly as how a bullet is “supposed” to.


Examples of that-

View attachment 539531

View attachment 539532





The key point here, is that like all bullets that rely on yawing as the mechanism for bullet upset- is variability. Not necessarily variability in “killing” or wound size created- all wounds have been very good to excellent, but in how the bullet behaves. If someone thinks that what a bullet looks like after it’s pulled out of an animal determines how well it kills, they’ll hate the DTAC NR. If, they only care how it kills, they’ll like it. A yawing bullet crushes a lot of tissue, and a rapidly fragmenting bullet creates very large wounds- they just do it differently.



The 115gr DTAC Noserings (esp. the deeper cut ones) are my preference for elk in 6mm. IIRC 16 of 18 have exited from 60 yards to 970 yards; all have created very good wounds, and all killed quickly. Even at 1,500 something FPs impact they tumbled and preformed very well.

Thanks for the explanation.

Another question I’d have would be in what case and why would you choose this over say a Berger? They sound somewhat similar.

I prefer a tipped bullet on deer, not much elk experience. Do you generally prefer a Berger or dtac style bullet for elk sized game?

Iv got a 7 twist creedmoor I should try some dtacs in. Hopefully Sierra keeps them supplied, seems like they have been dropping the ball more than the other manufacturers.

 

[Formidilosus]

Thanks for the explanation.

Another question I’d have would be in what case and why would you choose this over say a Berger? They sound somewhat similar.

No, not really. I mean yes- in that both tend to yaw. However, Berger VLD’s have thin jackets and consistently fragment above 2k’ish fps impact, and abut 50% of the time below that to about 1,800’ish FPS. The DTACs aren’t consistent in whether they tumble and fragment or just tumble.


Also,

I forgot to write above that they have a rebated boattail which tends to shoot well even when a barrel is getting “shot out”.

I prefer a tipped bullet on deer, not much elk experience. Do you generally prefer a Berger or dtac style bullet for elk sized game?

No. If I had my druthers, I would prefer a 115gr to 120gr tipped match bullet, preferably a TMK. The reason being is that I do prefer the consistency that a plastic tipped, heavy for caliber, thin jacketed bullet provides- it penetrates 0-2” and then begins to upset/fragment from the front; and it does so from 3k+ FPS to 1,800’ish FPS impacts, and at those weights they would most likely exit.
Also, when I/we miss an animal or get a fringe hit, it’s generally high or low (not left/right). A bullet like a Berger or DTAC that goes high and just clips the back with a long neck length of 3-6”, may or may not cause the animal to fall due to the TC effecting the spinal cord, but regardless it’s almost never fatal and the animal recovers and takes off. A rapidly fragmenting bullet ala ELD-M/X, TMK, etc., creates a much larger wound that often sends a fragment into the body cavity or otherwise permanently effects the spinal cord. In any case, it causes more tissue damage whether high or low, and leaves more blood for follow up.


Having said that, tipped bullets do have a operating window that they upset in. A bullet that consistenly yaws (tumbles) doesn’t really. Now some tipped bullets yaw and even fragment some at very low impact velocities, but most don’t. Also, the NR DTAC’s exit, which if I had my preference I would choose.

The reason I like the NR DTAC’s on elk is because they kill very well from muzzle to at least 1,500’ish FPS impact, they almost always exit while producing a good wound channel, and they are stable and consistent in all conditions (I.E., not fussy). I have zero issues killing elk at very long range with them.

For deer (and elk to be clear), in normal 6mm’s such as 243, 6cm, XC, ARC, etc. the 108gr ELD-M and 103gr ELD-X are fantastic and would be my choice.


This is a 108gr ELD-M from a 6cm at 636 yards, pulled out of an elk after penetrating ribs and “shoulders” shot by Ryan’s wife Tanya-

Iv got a 7 twist creedmoor I should try some dtacs in. Hopefully Sierra keeps them supplied, seems like they have been dropping the ball more than the other manufacturers.

They’re good bullets. For deer, the easy button is the ELD-M and X’s. The 112gr Barnes Match Burner is a violently upsetting bullet as well.

 

[PathFinder]

The 115gr DTAC Noserings (esp. the deeper cut ones) are my preference for elk in 6mm. IIRC 16 of 18 have exited from 60 yards to 970 yards; all have created very good wounds, and all killed quickly. Even at 1,500 something FPs impact they tumbled and preformed very well.

Form,
In reference to the deeper cut, I understand that the nose ring cut can be adjusted. My assumption is that the ones that can be ordered from DTAC are somewhere in the middle, around .030". Is it worth having a cutter and customizing that depth or are the ones on the site adequate?
As a related question, any positives/negatives to the TBN coated ones? I've research the coating and most results seem positive. Any reason not to order coated ones at the same price?

 

[Formidilosus]

Form,
In reference to the deeper cut, I understand that the nose ring cut can be adjusted. My assumption is that the ones that can be ordered from DTAC are somewhere in the middle, around .030". Is it worth having a cutter and customizing that depth or are the ones on the site adequate?

I think as they come is .025…? In any case they are adequate, however .050 cut perform better- they fragment more often, and at lower velocity.

If you were going to use them regularly- as in that’s your bullet, yes I would either get ones at .050 cut or get the cutter. If it’s just infrequent, or on elk…. Eh.

As a related question, any positives/negatives to the TBN coated ones? I've research the coating and most results seem positive. Any reason not to order coated ones at the same price?

Yea the TBN ones are worth it. I would pay extra.

 

[ElPollo]

FF with this rifle. This will probably be the last hunting trip for this barrel. It will become the FF barrel at UM. Quite a few 6UM on order now.

A Nilgai will be a great test. I hope to get a good close shot in the shoulder. Hope to shoot a few hogs too.


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Nilgai down? How did it go?

 

[Ryan Avery]

Works on pigs

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[PathFinder]

Works on pigs




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Looks like a good opportunity for some terminal testing! I'm interested to hear your final take on the performance on the smaller critters.

I finally got ahold of the guy I needed to at Tubb/Accuracy Reloading. He didn't sound real enthused about doing a custom .050" nose ring cut on one box of 500, but he said he'd look into it and get back to me. That was yesterday morning. Maybe if we organize some kind of group buy they'll be more interested in it. Without buying a nose ring cutter and modifying some of the thicker jacketed bullets on the market I'm not sure there's another great option with the 115 Berger VLD H currently unavailable.

 

[Ryan Avery]

Lane’s Nilgai,
Shot 150 yards slightly quartered, went 20 yards.

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[PNWGATOR]

Well done Lane!

 

[ChrisAU]

Lets talk about what really matters.

Does anyone else keep reading it as "sixum" vs "six you emm"

 

[BjornF16]

Lane’s Nilgai,
Shot 150 yards slightly quartered, went 20 yards.

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Ryan, curious about what the “guide” or property owner thought about using a 6mm bullet on Nilgai?

Several of the guides for nilgai insist/recommend .30 cal magnums…

 

[Gorp2007]

Lets talk about what really matters.

Does anyone else keep reading it as "sixum" vs "six you emm"

My first thought is always 6 Ultra Mag, but I like "sixum!"

 

[PathFinder]

Tubbs came through, one box of 500 coated, deep cut 115 DTAC are on the way. Just waiting on my barreled action and dies now.

 

[Ryan Avery]

6UM vs. a pig, notice the Nalgai in the top left corner.

 

[Ryan Avery]

Ryan, curious about what the “guide” or property owner thought about using a 6mm bullet on Nilgai?

Several of the guides for nilgai insist/recommend .30 cal magnums…

We had to do some sweet talking. They want a 200-grain bullet doing 3000FPS as a minimum.

 

[BjornF16]

We had to do some sweet talking. They want a 200-grain bullet doing 3000FPS as a minimum.

Did they learn anything?