Measuring Shoulder Setback?

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Newbie question here but does FLRS or Neck sizing push the shoulder back? Or is there a specific die that does that?
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FLRS pushs the shoulder back as well as size the body & neck. A Redding body die does the same as a FLRS die EXCEPT the neck area is not touched. Always FLRS before trimming brass, because the OAL of the brass gets longer on sizing. When the body is sized the brass moves forward.
 
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This thread is becoming more interesting.

Is it fair to assume one has already eliminated any variable of axial alignment of the bullet to the bore (i.e. eliminated runout to the best extent practical)? This is where I find I get the biggest bang for the buck. I have two guns (221 Fireball and 25-06 Rem) that I reform brass (223 and 30-06) both provide me with thicker necks than standard factory brass. I turn them to be within .002" chamber neck diameter and FL size. The ammo is wonderfully accurate in my stock rifles.
 
While we are on neck tension, has anyone measured to the best of their ability what kind of neck tension produces the best accuracy? I actually happen to believe that neck tension is fairly critical for an accurate round but have not proved one way or the other.

With my Lee Collet Neck die I was getting very minimal neck tension on once fired rounds, and more firings after I was getting almost none. I ended up sanding down the mandrel to get a bit more and have ended up on average of around .0015" of neck tension, sometimes less if the case is becoming work hardened. I would ideally want around .0015"-.002" on a regular basis as I feel this would produce the best accuracy with some durability qualities as well. I ordered another 2 mandrels from Lee to play around with different sizes and also be able to get adequet neck tension from work hardened brass with the smallest mandrel. Anyone else have opinions on neck tension?
 
Something vague, by reducing the mandrel size for your work-hardened brass you are attacking the symptom rather than the root cause. Annealing will be your new best friend. As you noticed, the work-hardened brass provides less neck tension which does affect accuracy. By annealing every 3rd or 4th firing, you will save yourself a lot of grief and aggravation not to mention components.

Using either Redding bushing dies or the Lee collet die, I have seen the most consistent results at .001 neck tension on the bench but that's not enough (IMO) for hunting rounds. I like .002 for hunting rounds. Also keep in mind that brass thickness varies from manufacturer to manufacturer. Not a big deal with the collet dies since they form to a fixed ID but since a bushing die forms to OD, you can see differences in your resulting neck tension.
 
something vague comments:
Wow, thanks man. I honestly have never thought about using fender washers as spacers for any of my dies as I was just in the mind set that I could use feeler guages to set the die back the same amount.
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You could also use Redding shell holders that come in .002-inch heights above the .125-inch standard. These speed up the process quite a bit and you don't have to handle an extra part in the process.

Note that all this shoulder set back stuff has to be measured else it's gonna get lost. A decent case gage, such as the RCBS Precision Mic will measure the head-to-shoulder dimension. Using this Mic on a fired case will give you a reading that you need to set the shoulder back .002-inch from.
 
Is the claim to better accuracy via controlled neck tension linked to pressure? I don't measure neck diameters ID/OD unless I'm setting up to neck turn so I can't comment to what tension I think I'm getting. It just seems unlikely that a small amount of neck tension will have a measurable influence on accuracy. I can see where a tight crimp on a cannilure might make a difference but on neck ID alone I'm not making the connection. This is particularly true on a 223 where you don't have a lot of neck to beging with.
 
Using this Mic on a fired case will give you a reading that you need to set the shoulder back .002-inch from
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Interesting......set the shoulder back......interesting
 
With my Lee Collet Neck die I was getting very minimal neck tension on once fired rounds, and more firings after I was getting almost none. I ended up sanding down the mandrel to get a bit more and have ended up on average of around .0015" of neck tension, sometimes less if the case is becoming work hardened. I would ideally want around .0015"-.002" on a regular basis as I feel this would produce the best accuracy with some durability qualities as well. I ordered another 2 mandrels from Lee to play around with different sizes and also be able to get adequet neck tension from work hardened brass with the smallest mandrel.
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When the brass is smashed against the mandrel, can this thin the neck wall thickness? I have seen this happen using standard FLRS dies with an expander over working the brass. But the virgin brass must be at the maximum neck diameter for a loaded round. When the neck wall thins to a certain point, it remains constant after that.
 
When the brass is smashed against the mandrel, can this thin the neck wall thickness?
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I don't think so but I have never measured case wall thickness before and after. The Lee Collet Die takes very little pressure to operate. If you apply too much pressure, the top pops off.
 
Walkalong's comment about setting fired case shoulders back when full length sizing them:
Interesting......set the shoulder back......interesting
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Well, how else will you have the case loose enough in the chamber to let the bolt close to exactly the same place for each shot? Especially when the bolt face isn't squared with the chamber axis.

If the case head doesn't slam back against the bolt face with even contact all over it when pressure peaks, it'll have contact at some point off center. That's a well known cause of "flyers" in extreme accuracy circles. Tests have shown it will open test groups by 1/2 to over a full MOA.
 
I think what Walkalong is trying to say is that in many of your posts you have stated that case shoulders actually get pushed back upon firing. Which makes some sense to me but not completely.

But the confusion I think lies in the fact that no matter what actually streches in the case, body (at the pressure ring), or the shoulder pushing forward you will still end up with a fired case that shows that the shoulder is more forward than you started. Therefore in both situations you will have to set the shoulder back. This is what I'm gathering anyways.

BTW, BartB I do own a Sinclair bump gauge which is very similar to the Hornady style guage that fits into the comparator body and measures a certain point (near the datum) on the shoulder. My Sinclair guage is actually angled to mimic the angle of the case shoulder to give a more consistant reading. But my issue has been that I am not seeing a difference after firing some factory and flrs rounds.

Yesterday I loaded some collet neck sized rounds that were flrs on the previous loading. These are some of the cases that have been giving me this constant measurement that is no different than when I flrs them. I got excellent accuracy out of the neck sized rounds but have not yet measured them. I will post back as to what I get for a measurement.
 
something vague:
I think what Walkalong is trying to say is that in many of your posts you have stated that case shoulders actually get pushed back upon firing. Which makes some sense to me but not completely.

But the confusion I think lies in the fact that no matter what actually streches in the case, body (at the pressure ring), or the shoulder pushing forward you will still end up with a fired case that shows that the shoulder is more forward than you started. Therefore in both situations you will have to set the shoulder back. This is what I'm gathering anyways.
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You're right. How much depends on case shape, pressure and firing pin impact force. In addition to the fired case having more headspace (head to shoulder dimension), its length is usually shorter; but only by a couple thousandths of an inch. It gets longer after it's sized; more with full length sizing, less with neck only sizing.

Get our your micrometer calipers, then measure a case (every possible dimension you can) after each thing you do with it. Load the first time, fire it, clean then resize it; these three things each change the case dimensions. Few people really do this; it's an education in itself. It sure was for me.

Another good educational process is to get 20 new rimless bottleneck cases. Prime each one, then load 15 of them starting with the first one having 15% below max charge writing the percentage on the case with a fine felt tip marker, the next one 14% below, then each remaing case another percent less until all 15 are loaded. Measure each case's headspace; head to shoulder with the proper tool; write 'em down in order 1 to 15. Then shoot load 1; 15% below max. Its primer will have backed out several thousandths and its case headspace will be shorter than before it was fired. Record all case dimensions for this. Repeat this for the next 14 rounds. Near the max load, primers will no longer be backed out of their pocket; proof the case shortens when smacked by the firing pin but stretches back until its head stops against the bolt face.

Caution: Reloading fired cases that have their primers backed out may not be safe so set them aside. If you can't full length resize them enough to push the shoulder forward back to at least what a new round has, don't reloade them. Save 'em for a show and tell on reloading. They're all numbered so one can see how they change with increasing powder charges.

You'll also see when the fired case headspace is no longer shorter than when new as well as when it starts to get longer. Interior pressure ballistics 101. Use the remaining 5 cases to do whatever test you've probably dreamed up after testing the first 15.

Another test to learn case dimensional changes when reloading rimless bottleneck cases, is to resize those first 15 cases to see how your die redimensions them. Folks'll learn more about this stuff doing this than reading all the books (or internet forums) in the world on it. The cost of those new cases plus their components may well be the best investment on reloading experience you'll ever make.
 
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You could also use Redding shell holders that come in .002-inch heights above the .125-inch standard. These speed up the process quite a bit and you don't have to handle an extra part in the process.
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I checked Sinclair and Midway. Is that what a standard Redding shell holder measure, or is this a special order?
 
Bart B. said:
Redding shell holders; a kit of several each .002" different than the next one.
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I have three of those Redding sets i.e. #1, #6 and #10 but you might be in for a surprise when you measure the shellholders. The #1 set has the following thickness measurements:

0.010" > 0.114"
0.008" > 0.116"
0.006" > 0.122"
0.004" > 0.120"
0.002" > 0.124"

Not very impressive really but as long as you know what you have there's always a workaround. I can't be bothered to contact Redding since I've had quite a few issues with their QC recently. One of the competition shell holder sets came with two of the same # holders in the box!

:)
 
Are shims for shellplates available commercially, or are you guys that use them making your own?

I'm interested because I am not able to get any setback on my .223 loads with an RCBS X die screwed down all the way + 1/4 turn. This is even with a Lee shellholder that measure 0.127"
 
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