sorting brass ?
- Thread starter Big Bob
- Start date
Jason Boersma
Silver $$ Contributor
1. yes
2. no but if you did use them as sighters. weight sorting cases does not tell you what the internal volume of the cases are because you can't tell where the extra weight is in the case. just my opinion
2. no but if you did use them as sighters. weight sorting cases does not tell you what the internal volume of the cases are because you can't tell where the extra weight is in the case. just my opinion
Case H2O volumn tells the story.
Big Bob said:
1. It depends what degree of precision you are aiming to get to. Your old and new brass are unlikely to be from the same production batch so I would keep them separate.
2. I don't see any benefit in weighing Lapua brass.
Regards
JCS
+1 Dave
The reason it's important to measure capacity on fully fireformed unsized cases is because that's the stable point of brass. It will never be more consistent.
If you were to measure new & FL sized cases, you would see H20 capacity all over the map in comparison.
Weighing brass means nothing real. It's a shortcut folks generalize themselves into.
I could take two cases of identical capacity, size them differently, and now capacity is different between them.
The way cases are formed and sized, their capacity is directly influenced by their springback to form.
Same weight though...
Now if you sort or cull brass by weight, how do you know what you're leaving for capacity difference? One case springs back different than another. . You don't know until you measure it.
So if you're going to measure it, then who cares what they weighed?
The reason it's important to measure capacity on fully fireformed unsized cases is because that's the stable point of brass. It will never be more consistent.
If you were to measure new & FL sized cases, you would see H20 capacity all over the map in comparison.
Weighing brass means nothing real. It's a shortcut folks generalize themselves into.
I could take two cases of identical capacity, size them differently, and now capacity is different between them.
The way cases are formed and sized, their capacity is directly influenced by their springback to form.
Same weight though...
Now if you sort or cull brass by weight, how do you know what you're leaving for capacity difference? One case springs back different than another. . You don't know until you measure it.
So if you're going to measure it, then who cares what they weighed?
CatShooter
The volume of a case is only relevant when it is under pressure, and has filled the chamber.
So whether the case is FL sized, or fired, or brand new is irrelevant. Once the case is underpressure, it will expand to fill the chamber (very early in the burning cycle) and THAT is the only volume that counts... so it is the volume of the metallic brass that takes up space in the chamber that counts.
That can only be determined by the weight.
So whether the case is FL sized, or fired, or brand new is irrelevant. Once the case is underpressure, it will expand to fill the chamber (very early in the burning cycle) and THAT is the only volume that counts... so it is the volume of the metallic brass that takes up space in the chamber that counts.
That can only be determined by the weight.
CatShooter
dmoran said:
We disagree - what a surprise - wow!!
CatShooter
mikecr said:
That is not how I see it... and not my experience in practice.
Well, there are conditions where capacity can vary without measurable effect. But with this, brass weight won't matter either.
A 6PPC/N133/~75Kpsi, pretty much nothing about the brass will matter. Same with a 300WM/H1000/25" fireball producer..
But with something more like a 6Dasher, 6.5x47L, or 7SAUM, consistent capacity matters more.
Consider a bit smaller case in the box analogous to one with a bit more neck tension(same effect).
Even it that 6Dasher case weighs exactly the same as the others, the result from it can be different(if seated off lands), and it's measurable.
A 6PPC/N133/~75Kpsi, pretty much nothing about the brass will matter. Same with a 300WM/H1000/25" fireball producer..
But with something more like a 6Dasher, 6.5x47L, or 7SAUM, consistent capacity matters more.
Consider a bit smaller case in the box analogous to one with a bit more neck tension(same effect).
Even it that 6Dasher case weighs exactly the same as the others, the result from it can be different(if seated off lands), and it's measurable.
bigedp51
Catshooter
Even Quickload tell you to measure case capacity of H2O of cases "fired" in your chamber, your measuring the internal size of your boiler room.
With the same lot of cartridge cases case weight tells you a good deal, BUT internal case volume can still vary. Not everyone makes cartridge cases to Lapua quality standards.
The Lupua case below only varied 1.2 grains in weight, the Winchester cases varied 6.5 grains and volume would vary more.
Because I'm retired and have nothing to do and all day to do it I sat down and checked my .223/5.56 cases for internal volume of H20. Case weight has very little to do with internal volume. I checked cases from the same lot of new Remington and Winchester cases and from my three five gallon buckets of once fired range pickup mixed brass of Federal, Remington and Lake City brass..
You might want to pick up some Vaseline because your going to get reamed over this one.
Even Quickload tell you to measure case capacity of H2O of cases "fired" in your chamber, your measuring the internal size of your boiler room.
With the same lot of cartridge cases case weight tells you a good deal, BUT internal case volume can still vary. Not everyone makes cartridge cases to Lapua quality standards.
The Lupua case below only varied 1.2 grains in weight, the Winchester cases varied 6.5 grains and volume would vary more.
Because I'm retired and have nothing to do and all day to do it I sat down and checked my .223/5.56 cases for internal volume of H20. Case weight has very little to do with internal volume. I checked cases from the same lot of new Remington and Winchester cases and from my three five gallon buckets of once fired range pickup mixed brass of Federal, Remington and Lake City brass..
You might want to pick up some Vaseline because your going to get reamed over this one.
CatShooter
I don't care - I would never measure the case capacity of sized cases...
I have found over the years, that if you take any of these things - weight of cases vs volume, ladder test, OCW test.... any of it - and you make up a bunch of samples and give them to someone, the differences rarely, if ever, show up.
When someone claims that a technique produces a specific result, it means nothing unless it can produce that result in a blind study.
Until that - I'll do it my way, and others can do it their way. Ain't America wunnerfful?
I have found over the years, that if you take any of these things - weight of cases vs volume, ladder test, OCW test.... any of it - and you make up a bunch of samples and give them to someone, the differences rarely, if ever, show up.
When someone claims that a technique produces a specific result, it means nothing unless it can produce that result in a blind study.
Until that - I'll do it my way, and others can do it their way. Ain't America wunnerfful?
CatShooter
amlevin said:
If you are using quality brass, the grove variations are very minimal, and can be checked with tools - the inside cannot. I had one batch of 300 pcs of Federal Gold Match that varied from 155gr to 176gr It showed on paper.
I shoot 6 Dashers and 300 WSMS at 1000 yards. I would never mix different lots of brass together. First thing I do is weigh all brass and sort by weight. Then I do all the case prep. When I shoot at 1000 yards all my cases are numbered. Records are no. 1 thru 10 and sighters are numbered s1 thru s8. They are never fired out of that rotation. When you get your target back you can see where each shot hit. I have never had to switch out a case because of going out of group. When shot one goes out this week; it doesn't go out to the same place next week. I have heard some say that a certain shot goes high or low every week and they switch it out; but I have never seen this happen.
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