Sorting Cases

[Mystic Precision]

Interesting.

Last time I checked, which was quite a while ago, benchrest competitors were using powder measures to dispense their loads. Are they now using high end electronic scales? If not, are powder measures repeatable to less than .1 grain?

I think we can agree that most benchrest competitors take ammo uniformity to the limit.

I remember reading an article in Precision Shooting some years ago that described some testing that showed weighing charges to a finer degree than a powder measure had no improvement in accuracy. I don't remember the details though.

This would seem to contradict the recommendations above for lab grade scales.

I have no dog in this fight (ok, it's not a fight, but you know what I mean). I'm just pointing out some stuff.

SR BR don't load to the possible limits. It doesn't matter at 100 and 200yds. Look at the loading protocols for LR BR and you will see the same methods we use in LR F class. The further you go, the more important these small tweaks are.

As Shockman indicated, annealing or consistent neck tension is one of those under utlised "free lunch". It really has a tangible effect on your grouping at LR. Not hard to do... just hard to do well. But there is now gear to ensure very consistent and repeatable results.

If you are doing it in a dim light room and pan of water, better to not do it at all. You WILL eventually create varying necks and that is worst then not annealing at all. Annealing is science with a pinch of art. Do it right and you will be very pleased with both groups and brass life.

So load to the necessities of your sport,and needs. There is no 1 perfect solution for every scenerio but there are lots of very good methods that WILL help in various situations.

And ultimately, let the holes in paper dictate how far you need to muck about.

Jerry

 

[BadAsMo]

neck tension!! what was that! did you say neck tension?? or was that neck tension? NO I meant consistent neck tension, or did I say neck tension?? no I meant consistent neck tension!!!
I started weighing brass one time, and got about ten pcs done when I started to think, I know that a dangerous thing when reloading, where is the difference in the weight from one piece to the next?? so if it is in the head where brass is thickest what would that have to do with pressure when the round goes off??? pretty sure the BIG deal is pressure!! so that was the last time I weighed a pc of brass. I'm pretty sure case volume is more important??? What I have found through experience is as my brass gets more fireing's my groups open up a little and I attribute this to hardening of the necks causing different grip tension which will effect PRESSURE! I have not resorted to anneiling yet as again I'm leary of consistency in the results, so I limit the amount of fireing's before replacing. I have found that a lot of the anal steps that shooters talk about are exactly that, ANAL. I believe it's all about PRESSURE when the round goes off! and I'm finding that some things we stress over are not that important if they don't affect pressure too much. I can see why Bench guys "throw" their loads, maybe one or two granuals of powder doesn't affect the pressure nearly as much as neck tension or some other variables??? I also live by the saying " if Lapua don't make it I don't shoot it" I think that eliminates a lot of brass prep. I would rather be shooting than loading so take this all as more internet opinion!!!
Marc

Certainly neck tension is something that needs to be controlled but to discontinue weighing brass in an effort to focus on case volume?? I don't get it. If 2 fire formed cases from the same lot weigh the same, then by default that have the same volume. So by using weight sorted cases that have been fire formed, you are ensuring case volume consistency.

If you don't weigh the fire formed cases you cant identify variations in case inside volume.

 

[Mystic Precision]

Certainly neck tension is something that needs to be controlled but to discontinue weighing brass in an effort to focus on case volume?? I don't get it. If 2 fire formed cases from the same lot weigh the same, then by default that have the same volume. So by using weight sorted cases that have been fire formed, you are ensuring case volume consistency.

If you don't weigh the fire formed cases you cant identify variations in case inside volume.

Sorry, wrong answer... variations in extractor groove machining is enough to cause cases to vary in weight. Big reason I stopped weighing cases. I found cases that weighed the same with different volume and vice versa.

Weighing cases was a lasy solution to tracking what was actually desired. If you want to measure case volume, measure case volume.

But after dozens and dozens of tested cases, I have found that volume rarely if ever varies from the same manf from the same lot. Lot to lot can be wonky so keep my brass segregated.

Neck ductility can be all over the map even with new cases from the same lot so now that is where I spend my efforts. Proper neck annealing is THE most difficult part of manf a case and a well guarded secret from some manf.

Being inherently lasy, I want to spend as little time at the loading bench and more time at the range. Over the years, I have just eliminated a bunch of stuff that don't seem to affect my grouping and focused on those that do.

Jerry

 

[BadAsMo]

Hang on a minute Jerry...

I'm layin down the BS card on you!

How on earth are you accurately measuring case inside volume to substantiate such a statement?
You are saying that you have a method of measuring case volume that is more precise than the variation in the machining of the extractor groove???

Please don't say you are filling cases with water because a half a drip weighs more that a couple thousandths of an inch variation in the machining. If this is the method you use, then all you are measuring is variations in the size of the last drip.

Please enlighten us Jerry, I'm dying to hear it.

 

[manitou210]

Weighing of cases may help some, but not near as much as NECK TURNING BRASS & UNIFORMING PRIMER POCKETS INSIDE & OUT and you need a good bullet seater Like Redding Or Forster.
Another thing very important to seat your primers at same depth, most primer tools seat primers differently. you need a hand help primer tool.not cheep + $125
I have checked speeds at muzzle and at 300m and will be testing speeds at 900m soon. if your es is high you will have troubles with elevation
manitou

 

[BadAsMo]

This is not an A or B choice. It's an A and B choice.
If you want to shoot precisely at long range you need to do it all.

Please note that an expensive priming tool is the very least important thing a guy needs. A standard loading press is all you need but the trick is to run the priming tool down far enough to lower the cam leverage on the press. If you do that, it becomes as sensitive as anyone could ever need. If you set up your primer seater in the press to bottom out the handle to seat the primer then you have maximized the mechanical leverage on the press and loose feel, thereby running the risk of crushing primers.

 

[358Rooster]

Hang on a minute Jerry...

I'm layin down the BS card on you!

How on earth are you accurately measuring case inside volume to substantiate such a statement?
You are saying that you have a method of measuring case volume that is more precise than the variation in the machining of the extractor groove.

Please don't say you are filling cases with water because a half a drip weighs more that a couple thousandths of an inch variation in the machining. If this is the method you use, then all you are measuring is variations in the size of the last drip.

Please enlighten us Jerry, I'm dying to hear it.

Keep in mind that there are variations in wall thicknesses, web thicknesses (or lengths), and machined dimensions. When cases are fireformed: the control here is that the outside dimensions of the portion of the case inside the rifle chamber are the same (or very, very close). It is very possible that you will have a different sized "chamber" within that case due to variations and inconsistencies / eccentricities that are not easily measured inside, despite the fact that it weighs the same as several other cases. Since volume consistency is what we're after, it seems only fitting that volume measurement is appropriate. Now, the method used to derive that figure is, as everything, debateable. The only thing practically available to the average enthusiast is water. Air gauging will give you accurate inside dimensions to calculate volume but would any of you think this practical? I have no idea what half a drip of water weighs versus a few thou of brass of a certain length over 'X' diameter. Can anyone here answer that?

Rooster

 

[cdn shooter]

I know with my .223 I had trouble tuning a decent load until I weighed cases to .5 grain tolerance. After I weight sorted I had no problem zeroing in on a load. I was sceptical up until this point and had thought the way Jerry does about case volume irregularities caused by brass thickness. I've even sorted using an eyedropper and water. THAT is a giant waste of time as its just SO slow. I even tried alcohol to cut the surface tension to get it right to the top of the case neck, never once saw any change in group size.

Oh and good luck keeping the drop size EXACTLY the same while filling a case drop by drop, just isn't going to happen.

 

[Mystic Precision]

Hang on a minute Jerry...

I'm layin down the BS card on you!

How on earth are you accurately measuring case inside volume to substantiate such a statement?
You are saying that you have a method of measuring case volume that is more precise than the variation in the machining of the extractor groove.

Please don't say you are filling cases with water because a half a drip weighs more that a couple thousandths of an inch variation in the machining. If this is the method you use, then all you are measuring is variations in the size of the last drip.

Please enlighten us Jerry, I'm dying to hear it.

You have your mind made up on what will and will not work. Far from me to try to sway your train of thought.

Enjoy....

Jerry

Just scan through this clip as I didn't edit and it is real time. At 500m with the FTR rifle I used last season. My methods seem to work for me. YMMV

 

[Mystic Precision]

I know with my .223 I had trouble tuning a decent load until I weighed cases to .5 grain tolerance. After I weight sorted I had no problem zeroing in on a load. I was sceptical up until this point and had thought the way Jerry does about case volume irregularities caused by brass thickness. I've even sorted using an eyedropper and water. THAT is a giant waste of time as its just SO slow. I even tried alcohol to cut the surface tension to get it right to the top of the case neck, never once saw any change in group size.

Oh and good luck keeping the drop size EXACTLY the same while filling a case drop by drop, just isn't going to happen.

Send me a pm or email.

Jerry

 

[Mystic Precision]

Keep in mind that there are variations in wall thicknesses, web thicknesses (or lengths), and machined dimensions. When cases are fireformed: the control here is that the outside dimensions of the portion of the case inside the rifle chamber are the same (or very, very close). It is very possible that you will have a different sized "chamber" within that case due to variations and inconsistencies / eccentricities that are not easily measured inside, despite the fact that it weighs the same as several other cases. Since volume consistency is what we're after, it seems only fitting that volume measurement is appropriate. Now, the method used to derive that figure is, as everything, debateable. The only thing practically available to the average enthusiast is water. Air gauging will give you accurate inside dimensions to calculate volume but would any of you think this practical? I have no idea what half a drip of water weighs versus a few thou of brass of a certain length over 'X' diameter. Can anyone here answer that?

Rooster

Someone got their thinking cap on....

Send me a PM or email and I will make your life SOOOO much easier.

Jerry

 

[Mystic Precision]

Weighing of cases may help some, but not near as much as NECK TURNING BRASS & UNIFORMING PRIMER POCKETS INSIDE & OUT and you need a good bullet seater Like Redding Or Forster.
Another thing very important to seat your primers at same depth, most primer tools seat primers differently. you need a hand help primer tool.not cheep + $125
I have checked speeds at muzzle and at 300m and will be testing speeds at 900m soon. if your es is high you will have troubles with elevation
manitou

If I am not mistaken, don't you shoot some very high scores?????

Jerry

 

[BadAsMo]

Keep in mind that there are variations in wall thicknesses, web thicknesses (or lengths), and machined dimensions. When cases are fireformed: the control here is that the outside dimensions of the portion of the case inside the rifle chamber are the same (or very, very close). It is very possible that you will have a different sized "chamber" within that case due to variations and inconsistencies / eccentricities that are not easily measured inside, despite the fact that it weighs the same as several other cases. Since volume consistency is what we're after, it seems only fitting that volume measurement is appropriate. Now, the method used to derive that figure is, as everything, debateable. The only thing practically available to the average enthusiast is water. Air gauging will give you accurate inside dimensions to calculate volume but would any of you think this practical? I have no idea what half a drip of water weighs versus a few thou of brass of a certain length over 'X' diameter. Can anyone here answer that?

Rooster

I’m sorry I don’t have a nice shooting video to post as an accolade to misdirect and substantiate the useless dribble I’m selling. All I have is a little common sense if you care to read on.

Every material on earth has density. That value can be used to determine any objects size (area) by its weight. If I was to tell you that a cubic foot of water weighed 62.42796 pounds, would the weight of that water change if it was in a bowl or a bottle? Of course not.

The same is true of brass. If you were to melt one of your cases into a little round ball and place it into your chamber, the amount of air in your chamber is the exact same as it would have been if you put the original case into the chamber. Since that is simple physics it cannot be argued by a rational mind.

So the fact remains that the weight of your cases does undeniably affect the volume of air left in your chamber.

The only thing left is on which side of the case wall is the air. If you are using fire formed cases then the air gap on the outside of the case is almost nothing. So, by simply weighing fire formed cases you are surely only really determining the air space within the case.

Obsessing over machining variations regarding rim dimensions on Lapua brass from the same lot is neurotic.

Since we do control the overall length of our cases it is important that the length of the cases be trimmed as close to the same on all cases being weight sorted.

Now there can be some very slight differences in the consistency of case wall thickness, but if two cases weigh the same, do you really think the slight variation in wall thickness between two cases is going to affect your speed even 2 feet per second? Even if it does, you have no means of determining it anyway, so why think about it?

Bottom line is that regardless of these slight variations in the distribution of brass, the volume of air inside two cases that weigh the same is the same. Its just physics.

 

[Mystic Precision]

I’m sorry I don’t have a nice shooting video to post as an accolade to misdirect and substantiate the useless dribble I’m selling. All I have is a little common sense if you care to read on.

Every material on earth has density. That value can be used to determine any objects size (area) by its weight. If I was to tell you that a cubic foot of water weighed 62.42796 pounds, would the weight of that water change if it was in a bowl or a bottle? Of course not.

The same is true of brass. If you were to melt one of your cases into a little round ball and place it into your chamber, the amount of air in your chamber is the exact same as it would have been if you put the original case into the chamber. Since that is simple physics it cannot be argued by a rational mind.

So the fact remains that the weight of your cases does undeniably affect the volume of air left in your chamber.

The only thing left is on which side of the case wall is the air. If you are using fire formed cases then the air gap on the outside of the case is almost nothing. So, by simply weighing fire formed cases you are surely only really determining the air space within the case. POINT 1

Obsessing over machining variations regarding rim dimensions on Lapua brass from the same lot is neurotic. POINT 2

Since we do control the overall length of our cases it is important that the length of the cases be trimmed as close to the same on all cases being weight sorted. POINT 3

Now there can be some very slight differences in the consistency of case wall thickness, but if two cases weigh the same, do you really think the slight variation in wall thickness between two cases is going to affect your speed even 2 feet per second? Even if it does, you have no means of determining it anyway, so why think about it? POINT 4

Bottom line is that regardless of these slight variations in the distribution of brass, the volume of air inside two cases that weigh the same is the same. Its just physics.POINT 5

1) When you weight something, you only determine the amount of stuff on your scale. You do not determine its distribution. You ASSUME it is as you want. You also do not confirm the alloy density... you assume it is all the same.

2) Then why bother weighing cases at all? or all the itty bitty neurotic things we do? did you know some BR shooters weight their primers?

3) Agreed but what about neck thickness? and other areas we muck with? What is that affect on mass?

4) Slight differences not being important yet you bother to weigh cases? I bet you would cull cases that had necks thicker on one side when measured. Why bother if that didn't matter?

5) There is that assumption again. First it matters, then it doesn't, then close is good enough.


I would have thought providing evidence to back ones opinions would have been of great value to someone like you with a ring....... NO?

Or is 1 opinion better then another?
Jerry

PS who says the alloy throughout a lot of brass is the same? Ever hear of a manf using more then 1 machine to produce their product run then batch mixing before packaging?

And finally, do you know where your Lapua brass is made?

Lots of assumptions

 

[gonnafail]

I am just getting in to precision reloading myself and have no experience either way. I am just enjoying this discussion.
I think there are good points made on both sides here and I would not be quite so quick to dismiss weighing cases.
One thing I think both sides agree on is that it is the internal case volume that ultimately matters. The question is whether case weight in any way correlates to internal case volume. After giving BadAsMo's post some thought I think there is some validity to a couple of his points which I will go through.

Essentially to see his logic you need to make a couple of assumptions. The first is that the outer dimensions of all the cases is exactly the same. In order for the weight method to work it is critical that the fire forming of the cases results in extremely consistent outer case dimensions. Once that is established you now have cases that are all the same volume. So the total volume of the brass and internal case volume combined is exactly the same case to case. If all of the total case volumes are the same than the difference in internal volume is entirely controlled by the amount of brass in the case. So a certain amount of the volume is being displaced by the brass. Regardless of how that brass is formed its displacing the same amount of volume with the remaining volume being internal case volume.

So if you made the first assumption that all cases are identical outer dimensions, you now can say that the difference in internal volume is the amount of brass. Now the next assumption needs to be made, brass density. In order for weight to be used as a determining factor in the amount of brass then the density needs to be consistent. If the density is not consistent than the same weight of brass would result in two different brass volumes and different internal case volume.

So does weighing correlate to internal case volume? depends on the accuracy of the assumptions you are making. Personally I would think that the density would be quite consistent and the real variable in this method is the consistency of fire forming the case. I would suspect that different hardness of brass, how many times it has been worked(resized), would result in different spring back of the brass after fire forming.

Jerry - If you have a different method of determining internal case volume please post or PM me as I would be very interested to hear what that method is.

 

[Grant Shave]

time to interject my 2 cents, the 5 most important things I have found are
#1 case length trimmed to 1thou of each case
#2 neck tension 100% exactly the same on every case, or your screwed from the start
#3 powder charge 100% exactly the same on every load, some what forgiving if your shooting the low to mid node, screwed if your on the high node
#4 seating depth, please, please measure off the ogive and not the tip unless ur loading a semi auto then who cares about accuracy
#5 every gun is an individual, and not all guns even though maybe the same caliber are likely to like the same thing, experimentation is required for all guns

oh and this is not in order of importance, they are all equally important if you want consistent and accurate loads

I neither weigh or volume test my brass, if I miss a shot I do what everyone else does and blame the "WIND"

 

[gonnafail]

Thanks Grant,
As I said I am new to precision reloading. In no way am I saying that this does or does not effect accuracy. I was just looking at the arguments that weighing cases can/cannot be used to reliably determine internal case volume.

For those of you who do weigh your cases I have an additional question. What do you do with the different values? Do you then develop different loads for each case weight? Do you sell or discard all brass that isn't the same weight?

 

[rnbra-shooter]

A few thought experiments (which if you want, you can run as real experiments too):

Question/Experiment No. 1: Does internal case volume consistency matter, at all?

Instead of sorting or measuring your brass, use a single cartridge case and fire a test string (you'll need to set up your loading gear on or near your shooting bench). What accuracy do you get? What degree of velocity consistency (m.v. SD or ES)? If you're doing your testing at 1000 yards, how much vertical in your group?

Question/Experiment No. 2: ....And if so, how much does it matter?

From your weight-sorted brass, choose the heaviest and lightest case you have. Ideally you'll have two cases that differ by 3-5 grains. Load them up with your best accuracy load. Also load 10-15 pcs of weight-matched brass with the same load.

Over a chronograph, and/or at a target set up at the longest distance available to you:
- fire your 10-15 rounds of weight-matched brass, as well and as carefully as you can (you are trying to shoot the smallest group that your equipment and skill can produce). Carefully record your shot fall.
- then without changing anything, fire your "really light" round and your "really heavy" round and record where they land.

How big is the group from your 10-15 pcs. of weight-sorted ammo? Is it bigger or smaller than the group you fired in "Experiment No. 1" with a single cartridge case? Are the muzzle velocity SD or ES any different?

Does the point of impact of your "light" and "heavy" round land inside your group, or outside your group? And if so, by how much?

What is the muzzle velocity of your "light" and "heavy" round? Are they inside or outside the spread of your 10-15 shots of weight-matched ammo?

 

[SND]

Though I don't weigh brass and don't plan to mess with that, I did find that run out is lower with once fired brass. Generally around .005" with new brass, and .001-.002" with once fired, with enough consistency that I don't bother dialing anymore.
Regarding neck tension I ended up making a couple other expander balls and now just keep it a .001 interference, I found with much more than that I was getting some shaving of the bullet even with good lead in chamfer.
Definitely is under 1/2moa, but haven't had the time or weather to figure out how much under.
So many variables, and a slight change in the sun/temp will easily throw off elevation so I learned.


Ahh one thing I forgot, other reason I went to just .001" interference for neck tension was that I noticed that too high a tension also caused some variation in seating depth. I measure with a tool I made that touches where the lands should be since bullet length does vary a bit... now they stay exactly the same from first to last, instead of some being .005"+ off randomly when tension was too high. (6.5mm)

 

[358Rooster]

Sorry I haven't been back here for a while fellas. I feel a bit like that little yappy dog behind the fence... At any rate, good exchange here! I do have a few more bits to throw on the fire

Comment on physics; objects of exact same weights, lengths, and external dimensions should have nearly the same chamber volume, despite slight differences in distribution and density of the material - agreed. Mostly. If all the afforementioned are strictly controlled but the distribution of the material is slightly different from case to case, where does that material of the same density go? If one case (of several of the same weight) has a thinner wall than any of the others in this lot, either: a) the material in the "thinner" case has a higher density or molecular weight, or b) material of the same density has moved somewhere and as said before, with all external dimensions being the exact same, the only place for it to go is into the chamber, thus decreasing the chamber volume slightly. Ha! Dispute that! Speaking of neurotic... Anyway, yes, the weight of a fireformed case must directly affect the volume of the chamber within that case but I don't think it's exactly as cut and dried as most of us would like to believe. Now, the QUANTIFIABLE difference all this makes is beyond me. For the shooting I do, cases of the same lot and strict preparation practises are as far as I go.

One more thing BadAsMo: is your water tap water or demineralized?

Mr Shave; how do you control neck tension 100%? I've long pondered this as, each case will react slightly differently after being exposed to heat and pressure cycles. I've noticed some cases of the same lot and same number of firing cycles will exhibit different perceived properties (ductility). Short of hardness testing, I can't see any way to control this 100%. Sure, you can anneal but unless you have a thermocouple attached to each case, your flame is the exact same temperature for each case treatment, and your cool down period is tightly controlled, you will get different ductility results. I realize you probably mean 100% - within reasonable means I think it's a good thing I don't have time and money to do experiments Anyone know of any government grants a guy could get for something like this?

The other thing is, even if you control your case length to within .001, if you're using a hand-operated chamfer tool, it will blow your efforts to hell. One important part of neck tension is contact area. If you trim all your brass to within .001 but hit it with the chamfer tool, you could have a chamfer depth of a couple thou, or 10 or 20 thou. Each one will be different and none of them are likely to be cut perpendicular to the axis of the case! The only way past this (that I know of) would be something like the Wilson trimmer setup with their chamfer tool that has a positive stop, making the depth of each chamfer the same. And in that case, you could have large variances in case length but if the bottom of the chamfer (where contact with the bullet begins) is in the exact same location from your datum point, you would have the best result possible. Now what about the location of the contact point at the neck / shoulder junction?

Okay, I'm done for now. I gotta go have a nap to recover. Rooster gots da brain pain!

Rooster