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how to get consistent neck tension??

hi everyone...

I would like some pro's here to help me with this and critique my hand-loading methods if possible.

My problem: my bullet seating depth is inconsistent. I am getting overall length variations upwards of .003 (maybe this is good? I was kind of hoping to have it to the nearest .001)

The cause: I believe i have inconsistent neck tension. I recently bought a KM arbor press with the force measurement indicator. Data shows a direct correlation between longer overall lengths after seating the bullet (measured to the o-give) and having to use more force to seat the bullet. I am however unable to draw any conclusions as to what is causing the increased neck tension on some cases and not others. In fact the data actually seems to be very random. When I have a case with more or less than average neck tension the Force measurement indicator does an excellent job of exposing it, but i just cant figure out what is causing it in the first place.

My loading process, on this particular batch was like this..... I am using 3 times fired brass. I trimed prior to the last firing. I first decap only and then put the brass into the wash (ss media). then i put brass through expander mandrel and turned a small amount of material off the necks. (first time neck turning this brass). I then chamfer and debur and run through bushing bump die (no button). I then prime, charge, and seat the bullet (bullets sorted by weight) with a Wilson seater. Is there something I can be doing here that i am missing to get the tension more consistent????

please give me your opinion... thank you


cartridgeanalysis2-2.png
 
nra-for-life said:
hi everyone...

I would like some pro's here to help me with this and critique my hand-loading methods if possible.

My problem: my bullet seating depth is inconsistent. I am getting overall length variations upwards of .003 (maybe this is good? I was kind of hoping to have it to the nearest .001)

The cause: I believe i have inconsistent neck tension. I recently bought a KM arbor press with the force measurement indicator. Data shows a direct correlation between longer overall lengths after seating the bullet (measured to the o-give) and having to use more force to seat the bullet. I am however unable to draw any conclusions as to what is causing the increased neck tension on some cases and not others. In fact the data actually seems to be very random. When I have a case with more or less than average neck tension the Force measurement indicator does an excellent job of exposing it, but i just cant figure out what is causing it in the first place.

My loading process, on this particular batch was like this..... I am using 3 times fired brass. I trimed prior to the last firing. I first decap only and then put the brass into the wash (ss media). then i put brass through expander mandrel and turned a small amount of material off the necks. (first time neck turning this brass). I then chamfer and debur and run through bushing bump die (no button). I then prime, charge, and seat the bullet (bullets sorted by weight) with a Wilson seater. Is there something I can be doing here that i am missing to get the tension more consistent????


please give me your opinion... thank you


cartridgeanalysis2-2.png
nra for life,
Erik is correct annealing would probably help but your process is all backwards, lets run through it.

De capping first sounds good, then clean them in your SS media then you should run it through neck die, a standard neck die is best for this job, ( not a bushing die) then trim, then inside chamfer, then run them through the expander, then turn the cases, then outside chamfer, then size them with your normal loading die run them back through the vibrator or at least clean any oil or lube from the inside of the necks, and load them, if your still have some tension trouble then you might try some graphite on the inside of the necks after your process you just went through before charging and seating. Most importantly you have to size the neck back then expand so you have a good fit on your neck turning tool, hope this helps some.
Wayne.
 
"I am getting overall length variations upwards of .003"

There may only be a perceived problem as Sierras can vary that much in length by themselves if you haven't length sorted them. Can you feel alot of difference in seating force from round to round? maybe the gauge is only showing the bullets initial entry force into the case and not the actual force?
Is a half pound of force excessive? when using a regular leveraged press that may be undetectable.
I would shoot them first before jumping to any conclusions as sometimes problems are only "discovered" when we get a new measuring device Lol.
I have some rounds fired 20 times with no annealing and there are slight seating force variations (surely many ounces of felt pressure) while seating on the arbor press but they still hold 1/2" of vertical at 300 yards (whoops corrected brainfart) when I can and if I used your strain force gauge would probably start second guessing something that is perfectly normal.

Plus since you are probably jumping the Sierras the exact OAL of the bullet to lands is not as critical like bullets that need to be seated exactly at the lands etc...
 
In2deep, did you say 1/2" vertical at 500 yards? Like .500 inch?
If so, caliber and number of shots?
 
Erik Cortina said:
You need to decrease neck tension. Annealing would also help.

okay...but regardless of reducing neck tension, shouldn't consistent neck tension, even if a little higher, still yield consistent seating depth??? i can reduce the tension by going down one bushing size no problem, but how does that make it more consistent?? what neck tension do you like to have for your competition shooting? thanks
 
bozo699 said:
De capping first sounds good, then clean them in your SS media then you should run it through neck die, a standard neck die is best for this job, ( not a bushing die) then trim, then inside chamfer, then run them through the expander, then turn the cases, then outside chamfer, then size them with your normal loading die run them back through the vibrator or at least clean any oil or lube from the inside of the necks, and load them, if your still have some tension trouble then you might try some graphite on the inside of the necks after your process you just went through before charging and seating. Most importantly you have to size the neck back then expand so you have a good fit on your neck turning tool, hope this helps some.
Wayne.

wayne you lost me here. could you please explain this in some more detail? why is it better to use a regular neck die (non bushing)....also why would i size the necks if i'm just going to expand them again for trimming?? so you use a dry case neck lube (graphite or mica) to actually lubricate the brass for the bullet seating?? i have been seating my bullets with nothing to lubricate. thank you
 
in2deep said:
"I am getting overall length variations upwards of .003"

There may only be a perceived problem as Sierras can vary that much in length by themselves if you haven't length sorted them. Can you feel alot of difference in seating force from round to round? maybe the gauge is only showing the bullets initial entry force into the case and not the actual force?
Is a half pound of force excessive? when using a regular leveraged press that may be undetectable.
I would shoot them first before jumping to any conclusions as sometimes problems are only "discovered" when we get a new measuring device Lol.
I have some rounds fired 20 times with no annealing and there are slight seating force variations (surely many ounces of felt pressure) while seating on the arbor press but they still hold 1/2" of vertical at 500 yards when I can and if I used your strain force gauge would probably start second guessing something that is perfectly normal.


Plus since you are probably jumping the Sierras the exact OAL of the bullet to lands is not as critical like bullets that need to be seated exactly at the lands etc...

the sierra bullets i do not believe are the problem. they are sorted by weight and i have randomly checked a lot of them to see the difference in length from the base to the o-give and i haven't found a lot of difference.

on the arbor press, yes you can both feel a lot of force difference and verify it with the force measurement feature of the KM, it is actually a very cool press, i just got it and i'm very impressed with it. i defiantly don't get this kind of "feel" seating on a threaded press with a large handle for leverage. you can tell when the initial seat happens and you can tell as the bullet is seated. the force to seat the bullet also corresponds with the overall length.

More force applied = the OAL is longer. Less force applied = the OAL is shorter. this must mean that the brass has some minor amount of spring back i'm guessing. maybe someone here has a more technical explanation for this.
 
6BRinNZ said:
nra - looking at the data you have 1 in 10 that is .003" deeper the rest are +- .001" (.002" spread). Is this typical of your results?

If you want to be within +- .0005" (.001" spread) then I would look to sort bullets by diameter and bearing surface.

Also I'm not sure from the data what the OD is measured (not calculated) with the bullet seated. The one case where it seated deeper I am curious as to its measured OD.

Annealing you will most likely (depending on the answer to my question above) get more consistency and you may go from 1 in 10 to 1 in 20 (as an example).

yes this is typical results.

what equipment measures the bullet bearing surface? what do you use to measure the bullet diameter and sort with enough accuracy to sort some??? I ask because i just checked like 10-15 .22 cal SBK's and they were all exactly .2235 on my caliper.

the OD and ID measurements were both taken prior to bullet seating... Well obviously i would have to measure the ID before seating the bullet. :)

here is the measurements of the necks after the bullet seating

#1-.2495
#2-.2500
#3-.2485
#4-.2485
#5-.2480
#6-.2490
#7-.2485
#8-.2485
#9.-2500
#10-2510???? wtf? this one took a lot of force too... ill bet it is going to be a flyer.

also i checked the diameter of all the bullets on these sample cases, they all measure 0.2235.
 
nra-for-life said:
bozo699 said:
De capping first sounds good, then clean them in your SS media then you should run it through neck die, a standard neck die is best for this job, ( not a bushing die) then trim, then inside chamfer, then run them through the expander, then turn the cases, then outside chamfer, then size them with your normal loading die run them back through the vibrator or at least clean any oil or lube from the inside of the necks, and load them, if your still have some tension trouble then you might try some graphite on the inside of the necks after your process you just went through before charging and seating. Most importantly you have to size the neck back then expand so you have a good fit on your neck turning tool, hope this helps some.
Wayne.

wayne you lost me here. could you please explain this in some more detail? why is it better to use a regular neck die (non bushing)....also why would i size the necks if i'm just going to expand them again for trimming?? so you use a dry case neck lube (graphite or mica) to actually lubricate the brass for the bullet seating?? i have been seating my bullets with nothing to lubricate. thank you
#1 A bushing die does not size the neck all the way to the shoulder neck junction, you need it sized the whole way so you can expand and push a donut out and turn the neck into the shoulder a bit so as to not form any donuts.

#2 You stated you already trimmed the brass prior to the last firing, I can only assume you meant turning the neck and your chamber is a lot larger then the expander mandrel so you have to size the neck down then expand it back so the neck is the correct size for your neck tuning tool's turning arbor.

#3 yes some people use dry lube to make seating more uniform so the seating depth is the same and so bullet release theoretically will be the same. I polish mine with 0000 steel wool then clean them shiny each time so there all the same.
Wayne.
 
Different strokes, etc. NO one that I know of that shoots short range benchrest wants the inside of his necks devoid of all powder fouling. If you like things that clean, go mop the kitchen floor. ;)I am sure that your wife will be delighted. I use an old bronze bore brush and run in in and out 3-4 times, to remove the boulders. I want to see an uniform haze of fouling that on the whole inside of my necks. I believe that it makes bullet seating force more uniform. The thing about using a one piece die before expanding is that with a bushing die you don't size all the way to the shoulder, and that part that you do not size may not be expanded, depending on your neck clearance, so when you turn that part it will end up thinner than the rest of the neck. (OD larger, more sticking out that gets cut off). If you are only skimming the necks, this is probably no big deal, but if you are turning relatively thin, I think that it matters. Just remember,, there is no prize for the shiniest ammo.
 
nra-for-life said:
6BRinNZ said:
nra - looking at the data you have 1 in 10 that is .003" deeper the rest are +- .001" (.002" spread). Is this typical of your results?

If you want to be within +- .0005" (.001" spread) then I would look to sort bullets by diameter and bearing surface.

Also I'm not sure from the data what the OD is measured (not calculated) with the bullet seated. The one case where it seated deeper I am curious as to its measured OD.

Annealing you will most likely (depending on the answer to my question above) get more consistency and you may go from 1 in 10 to 1 in 20 (as an example).

yes this is typical results.

what equipment measures the bullet bearing surface? what do you use to measure the bullet diameter and sort with enough accuracy to sort some??? I ask because i just checked like 10-15 .22 cal SBK's and they were all exactly .2235 on my caliper.

the OD and ID measurements were both taken prior to bullet seating... Well obviously i would have to measure the ID before seating the bullet. :)

here is the measurements of the necks after the bullet seating

#1-.2495
#2-.2500
#3-.2485
#4-.2485
#5-.2480
#6-.2490
#7-.2485
#8-.2485
#9.-2500
#10-2510???? wtf? this one took a lot of force too... ill bet it is going to be a flyer.

also i checked the diameter of all the bullets on these sample cases, they all measure 0.2235.

If I understand correctly you have ~.002" spread in loaded OD? Would the one that seated in further have been #5?

Edit - just answered my question by looking at your chart. Putting it all together - the one round that went out of the norm was #5 2.0715 base to ogive (it seated deeper than the others) and coincidental that also has the smallest OD loaded. To me this makes sense.

With respect to neck thickness consistency there are two measurements that are important. The wall thickness variation within the same case and wall thickness variation between cases, in your case this is ~.002" which is too much.

Assuming that I have understood everything, I think that neck thickness consistency between cases will provide your greatest consistency gain at this point, as you clearly don't have .002" variation in bullet diameter.
 
I'm not a BR shooter so if you are looking for BR accuracy you may want to ignore this but I use a Lee Collet. If I use technique vertical is not a problem at all, and I don't have to turn anything..
 
Particularly for unturned case necks, I think that using Lee Collet Dies may give the very best results, even better than using a bushing die, on chambers where there is a lot of neck expansion (factory). If you need to size the body and bump the shoulder, you can do a two stage process with a body die after the collet. (I have found the order to matter.) It should be remembered that the way that you change neck tension with a collet die is to change the mandrel diameter. These dies may require a little detail work on the collet, but it is nothing that the average shooter can't handle. That was an excellent suggestion.
 
BoydAllen said:
...If you need to size the body and bump the shoulder, you can do a two stage process with a body die after the collet. (I have found the order to matter.) ...

I'm curious, I don't have any data to back it but my thought has always been that when I do either FL or shoulder bump I do it before I run them through the collet sizer with the idea that that way the neck didn't get skewed by one of the other operations. Have you found that doing the collet sizing first is a better sequence?
 
BoydAllen said:
Different strokes, etc. NO one that I know of that shoots short range benchrest wants the inside of his necks devoid of all powder fouling. If you like things that clean, go mop the kitchen floor. ;)I am sure that your wife will be delighted. I use an old bronze bore brush and run in in and out 3-4 times, to remove the boulders. I want to see an uniform haze of fouling that on the whole inside of my necks. I believe that it makes bullet seating force more uniform. The thing about using a one piece die before expanding is that with a bushing die you don't size all the way to the shoulder, and that part that you do not size may not be expanded, depending on your neck clearance, so when you turn that part it will end up thinner than the rest of the neck. (OD larger, more sticking out that gets cut off). If you are only skimming the necks, this is probably no big deal, but if you are turning relatively thin, I think that it matters. Just remember,, there is no prize for the shiniest ammo.
Boyd,
I would never contradict what you would have to say, and after they have been fired I do the same as you but when I originally prep the bras I polish all the scratches and whatever from the inside of the necks, I usually inside neck ream then polish with 0000 steel wool, I was taught this by a man that wins quite often at 1K so I have followed his lead. I agree with you in that the carbon that is on the necks acts as a lube so you never want to remove all of it and looking back at the op He is using 3X fired brass so I should have explained that better.
Wayne.
 
6BRinNZ said:
If I understand correctly you have ~.002" spread in loaded OD? Would the one that seated in further have been #5?

Edit - just answered my question by looking at your chart. Putting it all together - the one round that went out of the norm was #5 2.0715 base to ogive (it seated deeper than the others) and coincidental that also has the smallest OD loaded. To me this makes sense.

With respect to neck thickness consistency there are two measurements that are important. The wall thickness variation within the same case and wall thickness variation between cases, in your case this is ~.002" which is too much.

Assuming that I have understood everything, I think that neck thickness consistency between cases will provide your greatest consistency gain at this point, as you clearly don't have .002" variation in bullet diameter.

okay thank you i think you may have nailed it on the head and solved my riddle for me.

the two cases that stand out are #5 and #10.

# 5 was the shortest from base to ogive. it required the least amount of force to seat, and also had the smallest Outside diameter after the bullet seating (thus indicating that it likely had a thinner neck wall than the rest assuming my other measurements are accurate.

#10 was the longest from base to ogive. it also (not coincidentally?) required the most amount of force to seat and had the largest OD on the neck after seating. logic would dictate it had a thicker neck.

this is what seems to make sense....

okay so new questions. what tool would you recommend to measure neck thickness??? is a caliper sufficient or do i need something else??

also, about neck turning...obviously i must not be using my neck turner (it is a km with cutter pilot) correctly or precisely enough. any quick thoughts on why i would have neck thickness inconsistencies after turning? it seemed as though i turned the entire neck, i.e.- the cut was deep enough to take material off the entire neck. although there is some wobble in the case while it sits on the mandrel, which at the time did give me pause for thought but i assume this is normal??
 
nra-for-life said:
6BRinNZ said:
If I understand correctly you have ~.002" spread in loaded OD? Would the one that seated in further have been #5?

Edit - just answered my question by looking at your chart. Putting it all together - the one round that went out of the norm was #5 2.0715 base to ogive (it seated deeper than the others) and coincidental that also has the smallest OD loaded. To me this makes sense.

With respect to neck thickness consistency there are two measurements that are important. The wall thickness variation within the same case and wall thickness variation between cases, in your case this is ~.002" which is too much.

Assuming that I have understood everything, I think that neck thickness consistency between cases will provide your greatest consistency gain at this point, as you clearly don't have .002" variation in bullet diameter.

okay thank you i think you may have nailed it on the head and solved my riddle for me.

the two cases that stand out are #5 and #10.

# 5 was the shortest from base to ogive. it required the least amount of force to seat, and also had the smallest Outside diameter after the bullet seating (thus indicating that it likely had a thinner neck wall than the rest assuming my other measurements are accurate.

#10 was the longest from base to ogive. it also (not coincidentally?) required the most amount of force to seat and had the largest OD on the neck after seating. logic would dictate it had a thicker neck.

this is what seems to make sense....

okay so new questions. what tool would you recommend to measure neck thickness??? is a caliper sufficient or do i need something else??

also, about neck turning...obviously i must not be using my neck turner (it is a km with cutter pilot) correctly or precisely enough. any quick thoughts on why i would have neck thickness inconsistencies after turning? it seemed as though i turned the entire neck, i.e.- the cut was deep enough to take material off the entire neck. although there is some wobble in the case while it sits on the mandrel, which at the time did give me pause for thought but i assume this is normal??
That is why I told you that you needed to size the case and then expand with a expander that goes with the neck turner for a precise fit.
Wayne.
 
bozo699 said:
That is why I told you that you needed to size the case and then expand with a expander that goes with the neck turner for a precise fit.
Wayne.

so when you put your case neck on the mandrel (the one on the cutter) it has no wobble????
 

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