No neck tension with Whidden non-bushing resizing dies

[fguffey]

Hello, I'm a beginner reloader just trying to reload my first batch of 6.5 Creedmoor shells. I'm using the Whidden non-bushing resizing die and seater die, Forster Co-ax press, once fired Hornady brass, and Berger 140 gr Hunting VLD bullets. I started out with the .262" expander ball and when I went to seat the bullet there was no resistance. Sure enough I could remove the bullet with my fingers. I tried going down to the .261" and then .260" ball expander with the same result. I even tried removing the expander completely and got the same result. Am I doing something wrong or could it be an out of spec resizing die?? Thanks!

Tom, I am the fan of reloaders starting out with basics, I do not recommend a new reloader start out in a dead run with all of the latest and newest gadgets. I understand reloaders are impressionable and very easily influenced because of a lack of critical ability. I would suggest you put away the expensive stuff and start with full length sizing dies. I did notice you started with 'neck tensions', I use bullet hold because I can measure bullet hold, I do not have tension gages that measure tension and I have no conversion for tensions to pounds. It would be nice if 1 tension was equal to 2.2 pounds, if that was possible I could use the formula for converting kilos to pounds.

F. Guffey

 

[dmoran]

....I did notice you started with 'neck tensions', I use bullet hold because I can measure bullet hold, I do not have tension gages that measure tension and I have no conversion for tensions to pounds. It would be nice if 1 tension was equal to 2.2 pounds, if that was possible I could use the formula for converting kilos to pounds.

F. Guffey

The word "tension" means "state of being stretched". When reloaders are talking about "neck tension" we are referring to a measured amount of stretch of the case neck on the bullet.

Example:
0.267" = measured neck diameter after sizing, but before seating a bullet
0.269" = measured neck diameter after the bullet is seated
0.002" = the difference, and amount of measured neck tension in inches

It has nothing to do with pounds or kilos or conversions there of, like you keep confusing yourself with.
The plain and simple; reloaders are referring to the measured amount they size down the neck in relationship to its stretched measurement of the loaded round.
Reloaders are not confused, that be you who is so confused (repeatedly).....

​

 

[SheepDog]

In spite of the fact that neck tension has to do with the amount of friction the bullet is held by the tension is circumferential and not linear. It does however have a correlation to the amount of pressure it takes to seat a bullet. It has very little correlation to how the bullet is held by the case once it is fired because the case neck expands just before the bullet moves. At that point there is no neck tension at all. To concern ones self with such matters will either drive one to madness or to the wisdom of what is most important to ones self in the shooting sports.

 

[jlow]

In spite of the fact that neck tension has to do with the amount of friction the bullet is held by the tension is circumferential and not linear. It does however have a correlation to the amount of pressure it takes to seat a bullet. It has very little correlation to how the bullet is held by the case once it is fired because the case neck expands just before the bullet moves. At that point there is no neck tension at all. To concern ones self with such matters will either drive one to madness or to the wisdom of what is most important to ones self in the shooting sports.

Think about this for a second, or millisecond for that matter, because this is what it is about.

The force you feel as you seat the bullet relates to a lot of things, such as neck initial ID, friction, case hardening etc. As it turns out, it also relates to what happens when the case is fired because all three of the above affects the timing and bullet release characteristics when the case neck expands.

More tension because of smaller initial neck ID means more delay for the neck to open up. Friction means when the neck starts opening up and the bullet is still in contact with the case neck, the bullet will have a harder time moving forward. Case hardening means again more pressure needed to open that neck up.

A change in timing in terms of milliseconds of course is exactly what accuracy nodes are all about.

 

[SheepDog]

The brass neck deforms to seal the chamber well below the approx. 8000 psi it takes the bullet to engrave in the rifling. The neck itself expands at about 2000 psi.
The pressure nodes are generated at the point that the bullet begins moving down the barrel. IIRC
The node is the sound wave moving through the steel (traveling several times the speed of the bullet) which is precipitated by the "bulge" in the barrel from the peak pressure pulse. Neck tension has little effect on the node timing, far less than the travel time of the bullet before it hits the lands and begins to engrave. At that point the chamber is "hit" with an "explosion" that resonates back and forth through the metal of the barrel - just like hitting a pipe on the end with a hammer. Nothing the bullet does before it engages the rifling does anything to cause pressure nodes in the barrel.

 

[jlow]

The brass neck deforms to seal the chamber well below the approx. 8000 psi it takes the bullet to engrave in the rifling. The neck itself expands at about 2000 psi.
The pressure nodes are generated at the point that the bullet begins moving down the barrel. IIRC
The node is the sound wave moving through the steel (traveling several times the speed of the bullet) which is precipitated by the "bulge" in the barrel from the peak pressure pulse. Neck tension has little effect on the node timing, far less than the travel time of the bullet before it hits the lands and begins to engrave. At that point the chamber is "hit" with an "explosion" that resonates back and forth through the metal of the barrel - just like hitting a pipe on the end with a hammer. Nothing the bullet does before it engages the rifling does anything to cause pressure nodes in the barrel.

No problem with everything you said except that it has no effect on the travel time of the bullet – it does for all the reasons I already mentioned and is not going to repeat. It does just like other small things like 0.03 grains of powder and 3 thousands difference in seating depth also can also do similar things. If you don’t know these things, it just means you have not had much experience reloading.

Tony Boyer, the author of "The Book of Rifle Accuracy" and who is a "living legend" among benchrest shooters in his book page 159 said "Each time a case is fired and sized (assuming the same neck sizing button), there is slight less neck tension holding the bullet. Consequently, the start time of the bullet as pressure builds changes slightly." This start time is exactly what I was talking about. Change in start time means change in barrel time and barrel time is what we are talking about when we talk about accuracy nodes.

 

[SheepDog]

What is it that causes the nodes in the barrel? What in your view causes the barrel to whip?

 

[jlow]

What is it that causes the nodes in the barrel? What in your view causes the barrel to whip?

If you want to understand what cause the nodes in the barrel and barrel to whip, you can read up on this on Chris Long’s article but for our discussion, the key part to understand is you want the bullet to exit the crown when it is the most “quiet” which is the optimal barrel time i.e. OBT.

Since you cannot change optimal barrel time except by cutting barrel length, you change the time the bullet reside in the barrel by affecting “neck tension”, powder weight, or seating depth.

 

[mikecr]

Neck tension is not interference fit, nor friction/pulling/seating force.
Neck tension manifests as spring back grip on seated bullet bearing, and we currently have no way to directly measure this.
Like SheepDog mentioned, it takes very little pressure expanding necks to fully release bullets. This, because when the neck has expanded only 0.0000000001" it might as well be a mile, as the bullet is completely free of neck influence before that. But, this tiny delay in confinement is enough to affect pressure peak timing.
If you want to 'normally' adjust tension using your spring back grip(producing ~1thou interference max), you can do so with length of that neck sizing against no more than seated bullet bearing.
You can also take neck tension to a way higher amount via FL neck sizing, which would bring donut area into tension, and binding of the seated base-bearing junction. I would not ever do that unless into a 'pressure node', as it would greatly contribute to tension variance.

Also, there are different nodes, windows, and conditions in tune.
There is at least
-Seating node, as sought with full seating testing (~Berger's recommended)
-Powder node, as sought via OCW
-Barrel node, as sought via LADDER, or TUNER
-Vibration window, cleared via OBT
-Pressure node, (reached with underbores), a point deep enough into diminished returns to diminish most other influences
-Primer striking window, set at best per primer and cleared of action/bolt/trigger/spring/striker/primer seating issues

-Various optimal/detrimental conditions like bag fill, gun balance, any shouldering or other pressure points, barrel fouling, barrel temp, powder temp, etc...

 

[jlow]

Neck tension is not interference fit, nor friction/pulling/seating force.
Neck tension manifests as spring back grip on seated bullet bearing, and we currently have no way to directly measure this.
Like SheepDog mentioned, it takes very little pressure expanding necks to fully release bullets. This, because when the neck has expanded only 0.0000000001" it might as well be a mile, as the bullet is completely free of neck influence before that. But, this tiny delay in confinement is enough to affect pressure peak timing.
If you want to 'normally' adjust tension using your spring back grip(producing ~1thou interference max), you can do so with length of that neck sizing against no more than seated bullet bearing.
You can also take neck tension to a way higher amount via FL neck sizing, which would bring donut area into tension, and binding of the seated base-bearing junction. I would not ever do that unless into a 'pressure node', as it would greatly contribute to tension variance.

Also, there are different nodes, windows, and conditions in tune.
There is at least
-Seating node, as sought with full seating testing (~Berger's recommended)
-Powder node, as sought via OCW
-Barrel node, as sought via LADDER, or TUNER
-Vibration window, cleared via OBT
-Pressure node, (reached with underbores), a point deep enough into diminished returns to diminish most other influences
-Primer striking window, set at best per primer and cleared of action/bolt/trigger/spring/striker/primer seating issues

-Various optimal/detrimental conditions like bag fill, gun balance, any shouldering or other pressure points, barrel fouling, barrel temp, powder temp, etc...

Mikecr – not sure I agree about your contention of the small degree of expansion and how the completely free the bullet of neck influences is all or none. We know from our own experience that rough seating is always a bad thing i.e. vs. smooth and the influence of proper chamfer. Because of this, I do believe that brief as it is, that short but brief interaction when the neck expands enough for the bullet to move but is still interacting with the neck has a significant effect on when the bullet is released. If not, how else would one explain the negative effect of rough seating?

 

[mikecr]

Never heard of rough seating influencing MV.
I know seating friction in itself does not.
I can switch back & forth from WS2 coated to bare bullets without affecting MV, and the WS2 coated seat with way less force (as measured). I could greatly increase seating forces by taking bullets and necks to squeaky clean. This would not affect MV either.

Barring any problems, a bullet will release just fine with ANY neck clearance.
But it may be that 1-2thou clearance is needed by some to manage any clearance, and not end up with an accidental interference fit. That sentiment makes sense. It could be that their runout is high enough to put necks in a bind, potentially putting bullets in a bind, and in such a case I'm sure bigger clearances alleviate that chambered tension(same applies with the rest of the banana).
So I am not suggesting anybody should turn & polish necks to 0.000000001" clearance.. I'm just making a point related to neck tension itself, and relatively small pressure to overcome it.

 

[jlow]

Never heard of rough seating influencing MV.
I know seating friction in itself does not.
I can switch back & forth from WS2 coated to bare bullets without affecting MV, and the WS2 coated seat with way less force (as measured). I could greatly increase seating forces by taking bullets and necks to squeaky clean. This would not affect MV either.

Barring any problems, a bullet will release just fine with ANY neck clearance.
But it may be that 1-2thou clearance is needed by some to manage any clearance, and not end up with an accidental interference fit. That sentiment makes sense. It could be that their runout is high enough to put necks in a bind, potentially putting bullets in a bind, and in such a case I'm sure bigger clearances alleviate that chambered tension(same applies with the rest of the banana).
So I am not suggesting anybody should turn & polish necks to 0.000000001" clearance.. I'm just making a point related to neck tension itself, and relatively small pressure to overcome it.

Rough seating in my experience significantly affect precision, have not measure MV since as you can imagine it’s hard to get consistently inconsistent roughness… but presumably so but as it is with seating depth differences, the effect on actual MV is small (hard to measure but real) but actual effect on precision is great.

 

[SheepDog]

After a quick read of both Chris Long's and RSI's dissertation on the events I still have to ask a question. How does neck tension, or seating depth modify the velocity of the bullet down the barrel. Powder weight changes do change the velocity of the bullet and the timing of peak pressures so it will change the timing of the bullets exit, but neck tension has no effect on the bullets velocity or the maximum pressures or even the timing of the peak pressures. Seating depth, as it approaches the lands can increase the pressure by making it harder for the bullet to accept the rifling as it get closer. This has been proven through tests with pressures versus seating depths and the farther from the lands the lower the pressures. In effect you are affecting the barrel timing due to the faster pressure rise times and increasing the amplitude of the pressure with the higher pressures.

I will have to study Chris Longs theory more but I can say that I already see inconsistencies that should be addressed. One is that the sound pulse traveling back and forth through the barrel will increase in amplitude as it approaches the muzzle of a tapered barrel in much the same way the sound waves are intensified when going into a cone or a funnel. You can make things sound louder by putting the small end of the funnel in your ear or make them quieter by reversing it and putting the large end of the funnel in your ear. This means the barrel variations will be stronger in a tapered barrel than in a bull barrel at the muzzle. The other problem is that at least some of the sound waves will be reflected by the bullet as it travels down the bore which will set up secondary waves that can amplify or diminish the main sound pulse. This is the theory behind the clamp on barrel tuners which have also been proven to work. (and when put in the wrong place can absolutely destroy accuracy.

So there are at least a few things that have to be worked out to make the OBT practice completely factual. It, like other theories, does seem to hold promise in working out an "easy" way to find accurate loads.

Thanks for the discussion and for the information.
Paul

 

[mikecr]

IMO, there are only two tuning attributes: POWDER nodes & BARREL nodes. You hope they coincide, or with a tuner you can make it so.
The rest are 'problems' to clear off the table.
SEATING node is a window independent of powder. You're either in optimum CBTO, or out of it. Out of it is a problem you'll never gain awareness of without full seating testing.
PRIMER striking is another problem in that you're optimum and consistent there, or not.
VIBRATION can be both a window and otherwise. Vaughn laid out a lot of vibration examples/testing in 'Rifle Accuracy Facts'. OBT is one offending vibration. But you don't tune these, they're set in the build. You steer clear of them with your load(and/or your build).

 

[dkhunt14]

In spite of the fact that neck tension has to do with the amount of friction the bullet is held by the tension is circumferential and not linear. It does however have a correlation to the amount of pressure it takes to seat a bullet. It has very little correlation to how the bullet is held by the case once it is fired because the case neck expands just before the bullet moves. At that point there is no neck tension at all. To concern ones self with such matters will either drive one to madness or to the wisdom of what is most important to ones self in the shooting sports.

I have seen a primer with no powder push a bullet down a barrel a ways. The neck was not expanded at all. It takes very little pressure to start a bullet. If neck tension did nothing, why do most BR and long range BR guys tune WITH IT? I could care less what books or ballistic programs tell me, what I care about is the holes in the target. Matt

 

[jlow]

After a quick read of both Chris Long's and RSI's dissertation on the events I still have to ask a question. How does neck tension, or seating depth modify the velocity of the bullet down the barrel. Powder weight changes do change the velocity of the bullet and the timing of peak pressures so it will change the timing of the bullets exit, but neck tension has no effect on the bullets velocity or the maximum pressures or even the timing of the peak pressures. Seating depth, as it approaches the lands can increase the pressure by making it harder for the bullet to accept the rifling as it get closer. This has been proven through tests with pressures versus seating depths and the farther from the lands the lower the pressures. In effect you are affecting the barrel timing due to the faster pressure rise times and increasing the amplitude of the pressure with the higher pressures.

I will have to study Chris Longs theory more but I can say that I already see inconsistencies that should be addressed. One is that the sound pulse traveling back and forth through the barrel will increase in amplitude as it approaches the muzzle of a tapered barrel in much the same way the sound waves are intensified when going into a cone or a funnel. You can make things sound louder by putting the small end of the funnel in your ear or make them quieter by reversing it and putting the large end of the funnel in your ear. This means the barrel variations will be stronger in a tapered barrel than in a bull barrel at the muzzle. The other problem is that at least some of the sound waves will be reflected by the bullet as it travels down the bore which will set up secondary waves that can amplify or diminish the main sound pulse. This is the theory behind the clamp on barrel tuners which have also been proven to work. (and when put in the wrong place can absolutely destroy accuracy.

So there are at least a few things that have to be worked out to make the OBT practice completely factual. It, like other theories, does seem to hold promise in working out an "easy" way to find accurate loads.

Thanks for the discussion and for the information.
Paul

Yes, even though things like neck expansion and bullets being pushed off a case seem to happen instantaneously, it of course does not and it happen over time, just a short period of time. However, regardless of how fast it happens, there are a true interaction which affects the timing of when a bullet exit a barrel.

A good way to think how things work is to go to more extremes. For instance if you jam a bullet in to the lands, we all know that this will significantly affect chamber pressure which in turn can affect MV. Neck tension is no different, just to a significantly lesser degree. Pressure builds up in a case when primer ignites followed by powder. The bullet of course is the first impediment to this increase in pressure and so higher neck tension obviously will require more pressure to move the bullet. At the same time, neck roughness will do the same thing. The neck cannot magically expand to an ID significantly greater than the OD of the bullet and so this has to happen.

Seating depth can also affect pressure and MV without the bullet being jammed for a number of reasons. One is different depths means the bullet is different distance from the crown. The other reason is the deeper the seat, the less the case volume, and the more pressure for the same amount of powder. Pressure of course affects MV and timing.

 

[BoydAllen]

I love it when people have elaborate theories about how things work that absolutely do not agree with hard data. It is so amusing. Neck tension absolutely has a significant effect on tuning. For instance, a fellow who has recently done very well with his Dasher does not anneal because the powder that works the best for him "likes" a lot of neck tension. In the world of 6PPCs, back in the day, one of the better shooters told me that his experience had been that 133 "likes" quite a bit of neck tension. I switched from a .258 bushing to a .257 (.0086 neck thickness for a .262 chamber neck) and noticed an immediate improvement.
Going the other direction, recently I advised a new PPC shooter, that is working with LT32 that my experience with that powder is that it prefers less neck tension than 133. He went up in busing size and his results improved. My advice: test everything, and believe your targets.

 

[XTR]

Well now, this thread went straight down the rabbit hole didn't it.

 

[AWLEAPHART]

A friend of mind got me to set his bushing die up for his 6.5CM. He purchased some more 6.5cm brass from Cabelas and the neck thickness was different. It was big enough that we had .002 neck tension and the new brass after resizing was letting the bullet fall into the case. The first set of brass was from 3 boxes of Hornady ammo he punched.
Anthony

 

[reubenski]

Everytime I have bought non-bushing dies in the past I've regretted it. Just not enough flexibility to match different neck thicknesses later on down the road and a lot of overworking the brass, especially for someone who doesn't anneal. Bushing dies aren't that complex a concept to understand for a beginner.

What's that quote I saw on someone's signature...?...."Tells the "man to buy once, cry once" and then tells him to buy a .308!"