Neck tension vs Concentricity

[Richard Coody]

hoop stress is really what we are talking about. i don't think most reloaders are really interested in the physics behind it but here is the formula. we use seating effort as a crude way of measuring it. consistency is more important than actual force in my experience. if you really want to know glue a strain gauge to your brass neck and seat a bullet and see what the reading.is


Hoop (Circumferential) Stress
The hoop stress is acting circumferential and perpendicular to the axis and the radius of the cylinder wall. The hoop stress can be calculated as

σh = p d / (2 t) (1)

where

σh = hoop stress (MPa, psi)

p = internal pressure in the tube or cylinder (MPa, psi)

d = internal diameter of tube or cylinder (mm, in)

t = tube or cylinder wall thickness (mm, in)

 

[johara1]

Yes you hit on it uniformity, I like to sort by 2-3 lb and color code them as I do its I shoot them in sets ... jim

 

[Milo 2.0]

Yes you hit on it uniformity, I like to sort by 2-3 lb and color code them as I do its I shoot them in sets ... jim

I have to ask, apparently you are using a 21st century style press to measure?
So, at 1K yards, what do you see on target between diff seating forces, how much adjustment?

 

[johara1]

I have to ask, apparently you are using a 21st century style press to measure?
So, at 1K yards, what do you see on target between diff seating forces, how much adjustment?

People give numbers and I find it hard to pin down do to conditions. I will tell you this it does matter vertical is less than the hight of the numbers on a target at 1000 if conditions hold but that doesn't happen too often. Neck tension is everything at 1000, I am now using the K&M they are very close but it doesn't leak. I shot a group once to see push and let off it held the number height and was 32" wide.... it matters ...jim

 

[johara1]

I guess the will work to a degree but I would use a 25 lb. scale would be a little better. jim

 

[Milo 2.0]

People give numbers and I find it hard to pin down do to conditions. I will tell you this it does matter vertical is less than the hight of the numbers on a target at 1000 if conditions hold but that doesn't happen too often. Neck tension is everything at 1000, I am now using the K&M they are very close but it doesn't leak. I shot a group once to see push and let off it held the number height and was 32" wide.... it matters ...jim

Thanks for that, my shooting at the time does not dictate an arbor style press, maybe it should, I demand a lot from my ammo but not BR precision. I go off feel of my coax< event though I just read that is impossible, lol, and cull the weakest seating force for close up shots. The harder seating ones tend to fall in place.
I want to try in line seaters and an arbor press, but feel it will put me one step closer to painting ceramics in some nut house.

 

[fguffey]

the hyd. gauges for measuring seating pressure or neck tension works good but so do the K&M set up.... jim

The hydraulic gage does not measure tensions. The gage is always marked off in pounds and the gage is not shipped with a 'tensions to pounds' conversion.

F. Guffey

 

[dkhunt14]

Thanks for that, my shooting at the time does not dictate an arbor style press, maybe it should, I demand a lot from my ammo but not BR precision. I go off feel of my coax< event though I just read that is impossible, lol, and cull the weakest seating force for close up shots. The harder seating ones tend to fall in place.
I want to try in line seaters and an arbor press, but feel it will put me one step closer to painting ceramics in some nut house.

Once you pull the handle on an arbor press, you will get that WOW factor. It isnt all about feel either. I believe it makes straighter ammo and more consistant seating depth. But the best thing is the WOW factor. Matt

 

[Milo 2.0]

Milo
You should try an arbor press they are really quite nice,
(Without the bathroom scale of course) the conversion rate I'm still working on.
Jim

Yes, I have wanted the 21st century hydraulic since it came out, more to prove to my friends how much neck tension matters more than producing better ammo for myself. My gear, rifles included, seem to produce the accuracy I want, taking it to the next level could never hurt. Repeatability is everything.
Under the condition of anonymity, it'd be fun to repeat conversations that are held concerning accuracy. I have a good one concerning 6XC brass and assumptions made.

 

[Milo 2.0]

Jim
At 600 yards I run a bushing that is .002 under a loaded round also I'm careful with seating pressure trying to stay as consistent as possible.
When and if I'm fortunate enough to try 1000 yards what advice would give me for selecting a bushing size just for starting direction?
Thx
Jim

I'm not Jim, but I'd shoot it first and then analyze it.

 

[fguffey]

I used tension gauges on the cables on light aircraft, they measured in lbs also

The first one I used was in the oil field, it weighed in thousands of pounds. It was necessary to count the number of cables running through the shives to get an accurate weight.

F. Guffey

 

[johara1]

The first one I used was in the oil field, it weighed in thousands of pounds. It was necessary to count the number of cables running through the shives to get an accurate weight.

F. Guffey

You guys amaze me, what are you driving at? to try to prove you know more about something than everyone never saw. I guess you are going to get in an airplane and set cable tension with something you can't hold in your hand, you best know how it works when you count the cables when there is one at a time.
When you start setting records and winning matches you can tell us how you did and how you had checked new tension. I'm done..... jim

 

[fguffey]

You guys amaze me, what are you driving at? to try to prove you know more about something than everyone never saw. I guess you are going to get in an airplane and set cable tension with something you can't hold in your hand, you best know how it works when you count the cables when there is one at a time.

You guys amaze me,

Thank you, and then we get to that part where you are confused about what we are driving at. Before the Internet there was bullet hold, for me? Not a problem because bullet hold can be measured in pounds, even thought tension gages measured tension for cables there is no such thing as tension; like 15 tensions or 10 tensions or 8 tensions = 9 pounds.

I am the fan of bullet hold, I can measure bullet hold in pounds, from the beginning I could measure the amount of effort necessary to seat a bullet in pounds, or the amount of effort necessary to pull a bullet. The one thing I do not have is a conversion for tensions to pounds.

F. Guffey

 

[jackson1]

Are we not as previously stated using these gauges a comparators- to find a similar reading from case to case? If so the what ever unit of measurement is unimportant. Has anyone found the magic seating force and if they have, is there a repeatable way to share that information? Just wondering.

 

[Richard Coody]

The hydraulic gage does not measure tensions. The gage is always marked off in pounds and the gage is not shipped with a 'tensions to pounds' conversion.

F. Guffey

guffey

in the engineering world tension is very easily calculated and is measured in newtons (metric units) or lbs (english units)

hoop stress is actually what creates your bullet hold. that can be calculated too!

measuring the force required to either pull or seat a bullet can be easily measured too

now devising a formula to relate the hoop stress in the case neck to the seating force required could be devised but there is one variable involved that would be most difficult to quantify. that is the coefficient of static and dynamic friction between the inside of the case neck and the bullet jacket. that is a variable we reloaders continuously try to keep consistent. so many things effect it.

best thing to do here is if you even want to take it this far is to use an arbor press with a force gauge and find out a range that your rifle likes and work to get your reloading process consistent in that range. just forget about the physics involved and let the target do the talking

 

[fguffey]

Are we not as previously stated using these gauges a comparators- to find a similar reading from case to case?

"using these gages a comparator ? Reloaders believe the word 'tension' is cool but there is nothing cool about measuring tension without measuring force measured in pound. ' I use interference fit, I use crush fit outside of reloading; problem, when I am on a reloading forum I am not dealing with reloaders that use interference fit and or crush fit outside of reloading. For years and years reloaders have had an infatuation with tension, for the same number of years I have asked for a conversion for tensions to pounds.

And then one day a manufacturer added a pressure gage to the bullet seating press, I was the only reloader that was not surprised the press did not come with a conversion from tensions to pounds and the gage measured in pounds.

F. Guffey

 

[Medic505]

 

[Milo 2.0]

LMAO, let's complicate this

 

[fguffey]

LMAO, let's complicate this

If you spent less time laughing and more time thinking you would spend less time looking for a tool that measures tension and more time using a tool that measures bullet hold in pounds.

F. Guffey

 

[Milo 2.0]

If you spent less time laughing and more time thinking you would spend less time looking for a tool that measures tension and more time using a tool that measures bullet hold in pounds.

F. Guffey

Politely piss off. I'm not certain why I do not have you on ignore, you can wreck a thread faster than anyone with your garbled musings, who really cares about your tools or tensions?
EDIT: Or your datums, or the fact that only you can move a shoulder in a supported die.
Us mortals speak in a universal language when it comes to loading, whether correct or not, because it becomes irrelevant if people understand what is meant.
No one, and I repeat, no one understands your garbage.