Sorting brass by water volume..HOW?

W

Wolfdawg6422

New member
How does one use water to sort brass? I mean, how does water stay inside the case to be weighed? If you use a primer, then the primer will factor into the weight.

If you use any material to block the flash hole, that too becomes part of the equation.

So, how is it done?

Wolfdawg
 
Wolf, Here is how I would do this. You might like to get a PIPET. There are 92 pages of these fancy calibrated eye dropper's in the Fisher Scientific Catalog. They are usually marked in ml, millimeters. Now find the weight of water in ml.
Take your trimmed to correct length case and fill with water. Note the ml it took to fill the case.
Now do the math. ml of water x weight of water will give you a number. If the cases vary the number will vary. Sort by number.
This is so much fun. :)
Centerfire
 
clean and full length size and br prep al the brass first....
for just volume, seat an inverted used primer in each case, wiegh the primed case, fill with 77f/25c water(i fill from a slow stream at the faucet).....tap the case to remove air, wipe case clear of excess, establish a close to flat miniscus(sp) .that is the shape of the water on the top of the case mouth...just be consistant. wiegh the water/case. the difference in wieght is vol. at 77f water is aprox 1 cc per gr. sort by tenths...... you will need a good lab type scale for this.....
since a typical loading beam scale is plus or minus .1, just the double wieghing of the case/case with h2o would put you at plus or minus .2....not very good in my opinion.

mike in co
Wolfdawg6422 said:
How does one use water to sort brass? I mean, how does water stay inside the case to be weighed? If you use a primer, then the primer will factor into the weight.

If you use any material to block the flash hole, that too becomes part of the equation.

So, how is it done?

Wolfdawg
Click to expand...
 
Last edited by a moderator:
doesn't the water drip out the bottom ??

mike in co
Centerfire said:
Wolf, Here is how I would do this. You might like to get a PIPET. There are 92 pages of these fancy calibrated eye dropper's in the Fisher Scientific Catalog. They are usually marked in ml, millimeters. Now find the weight of water in ml.
Take your trimmed to correct length case and fill with water. Note the ml it took to fill the case.
Now do the math. ml of water x weight of water will give you a number. If the cases vary the number will vary. Sort by number.
This is so much fun. :)
Centerfire
Click to expand...
 
You zero your scale with the empty plugged case. Then you eye drop fill it with water while it sets on the scale.
I put water in a cup next to the scale and add a few drops of alcohol to it to reduce meniscus formation. I use a paper towel corner to bring water level at the mouths.
For plugging of flash holes, I stand the cases(on the scale) on a plastic golf tee inserted into the flash hole.
I don't worry about the little bit of carbon inside fired cases, or to have a higher resolution scale than .1.
Capacity departures from the pack are obvious.
It doesn't make sense to capacity check anything but fully prepped and fully fireformed -unsized cases.
With this, they're as close to the same volume as they're ever going to be.
 
MIKE,
i use sized...cause its closest to actual firing volume.......different than fired volume( depending on rifle type..br vs all else) and that allows me to do computer based load workup....
the other mike
 
mike in co said:
MIKE,
i use sized...cause its closest to actual firing volume.......different than fired volume( depending on rifle type..br vs all else) and that allows me to do computer based load workup....
the other mike
Click to expand...
It does matter a twit what the actual weight of the water is. What matters is that the variance case to case is minimal. Therefore, use fired cases before you remove the primers. Pipette water into them, on the scale. practice on getting the same "bubble" of water above the neck. that is why a pipette. need tight control on water going into the case
 
unless, as i pointed out one also wants to calculate some potential loads....based on ACTUAL CASE VOLUME...can't do that with just comparisons of case to case.
mike in co
David Halblom said:
It does matter a twit what the actual weight of the water is. What matters is that the variance case to case is minimal. Therefore, use fired cases before you remove the primers. Pipette water into them, on the scale. practice on getting the same "bubble" of water above the neck. that is why a pipette. need tight control on water going into the case
Click to expand...
 
i don't have enough true br experience to say yes or no, but it is one more variable...and if one can take it to zero...well then it is out of the equation.
i have one set of brass for my 223 br rifle that is all the same wieght and the same volume. use them in matches.
my 1000 yd brass is plus or minus 0.1 gr..but no volume checks.......
mike in co
 
Has anyone ever emptied and re-weighed cases? In other words weighed them twice? Is water a repeatable medium?

I have my doubts

al
 
yes...the clue is getting them dry and using the same temp water....
tapping the case to release air, filling with a non aireated stream....

mike in co
alinwa said:
Has anyone ever emptied and re-weighed cases? In other words weighed them twice? Is water a repeatable medium?

I have my doubts

al
Click to expand...
 
I am not a benchrest shooter BUT if I was a really serious benchrester I would sort them when shooting them for groups, by the chrono speeds AND where each one grouped. After sorting them in this manner I would see how my next range session went. I bet I would have tighter groups over all.
 
What I've learned so far

Use fired fully prepped cases.

One way to record results is to place the cases in a loading block. The plastic MTMs work the nuts. Preferably in order by weight. Then using a ruler make 50 blocks on a piece of paper. Record the case weight and then the case weight with primer. Then as you go along write in the filled weights as measured with a good digital scale.

I like to weigh mine at least twice to verify the results. If it comes out more than +/- .04g (and it does maybe 20% of the time) or looks to be way off from the others, I’ll weigh them some more till I’m satisfied with the results.

You can use the flat backside of a knife to get the water at the case mouth level.

Keep a paper towel handy to wipe any water from the outside of the case.

You can fill them fairly accurately from a very slow running tap. Fill and empty them one time before you start capacity weighing to get the inside carbon wet.

If you’re doing cases that have just been fire-formed you may want to FL size. A lot of times it takes a couple firings for all the cases to uniform out. FL sizing to the shortest headspace reading may help to uniform your once fired cases. So it’d probably be better to wait till they have a couple firings on them if you want to do it unsized. Not sure that you’d find much of a difference in what cases get sorted out using the sized or unsized approach.

Keep them in the loading block till you’ve finished sorting out. Sort them out into the same place in another loading block. Be suspicious of any case that when empty is in the mid range, but when filled is way off from the filled mid range. Weigh it a couple times again to be sure you didn’t make a mistake.
 
Here's the results I got from a bag of WW 308 cases that had just been prepped and blown out to 338 Federal. If Quickload is right the bag had a 26fps inherent spread in it. By taking out the 12 smallest and largest capacities that spread was reduced to 6fps.


152.54- 59.26
153.28- 58.96
153.30- 59.02
153.50- 58.84
153.52- 58.96
153.54- 58.87
153.56- 58.76
153.60- 58.90
153.64- 58.84
153.94- 58.74
153.96- 58.73
153.98- 58.76
154.02- 58.72
154.06- 58.74
154.08- 58.63
154.10- 58.63
154.10- 58.70
154.30- 58.58
154.30- 58.48
154.32- 58.52
154.36- 58.64
154.36- 58.54
154.44- 58.61
154.54- 58.68
154.56- 58.65
154.58- 58.64
154.60- 58.59
154.62- 58.56
154.68- 58.75
154.72- 58.65
154.74- 58.65
154.76- 58.67
154.78- 58.79
154.84- 58.73
154.84- 58.66
154.84- 58.62
154.84- 58.59
154.86- 58.69
154.98- 58.80
155.00- 58.70
155.04- 58.65
155.08- 58.62
155.26- 58.56
155.30- 59.32
155.36- 58.66
156.20- 58.60
160.34- 58.06
162.32- 58.03
 
most br shooters shoot 6ppc, they shoot n133 for powder. most br shooters throw charges. we have shown over and over, that thrown charges of n133 vary plus/minus 0.2 with an ocassional 0.3. this means a spread of 0.6 gr. so your test shows nothing unless done with a lab quality scale.

mike
 
Doing all this weighing may be next to useless for short range benchrest. I don’t know. But nowadays here in PA the majority of benchrest shooting is being done at groundhog shoots(usually 200, then 300, then 400 or 500) and at long range. I can’t figure out how short range, where it comes down to .001” isn’t as anal as the longer ranges. Doesn’t 20fps equal at least a couple .001s at 100?
 
bill,
there are lots of lemmings in short range benchrest.
they are not thinkers...they strictly follow.
i'm not a big br shooter, but i can see that the more variables i remove from the equation, the more chances i have of being consistant.
most still throw charges even though the data has been presented that it is not consistant with thier favorite powder. the edge goes to those that use a chargemaster at the range or who can preload and use a lab scale.
220 russian brass is very good, so they see no need to wieght sort. it aint perfect.
i'll admit my volume sorting was done when i had just one gun and was trying hard to make it competitive.
i only wieght sorted my 300 win mag brass...but it is in two groups that are plus or minus a tenth.
yes to your question but there are few that recognize the issue and fewer that will work on it.
mike in co
 
tricrown said:
Doing all this weighing may be next to useless for short range benchrest. I don’t know. But nowadays here in PA the majority of benchrest shooting is being done at groundhog shoots(usually 200, then 300, then 400 or 500) and at long range. I can’t figure out how short range, where it comes down to .001” isn’t as anal as the longer ranges. Doesn’t 20fps equal at least a couple .001s at 100?
Click to expand...

short range guys tune for those velocity variations, this is what 'tuning' IS
 
al,
how does one tune for a variation in case to case volume when throwing charges that vary by plus or minus 0.2 ??? thats has to be one large sweet spot in the tune ...

if ya see my point....
mike
 
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