This process of filling a case with water and weighing the contents is something I have not done. I have always just got some fine ball powder, like H-380 and gently filled cases and took a straight edge and scraped off the excess and weighed that. In this way I could make comparisons from one brand to another and determine which had the most and the least internal case capacity. From there, I could determine that this brand has X% more capacity than that brand, which is really all I was after anyway.

Those who are familiar with reading graduated cylinders know of something called the hibiscus, that property of water that when put into a narrow cylinder will curve, and we read the bottom of that curve.

When water is put into a typical bottled neck case, the water will curve in the narrow neck. At what point do you call it good? Getting water spillage on the scale doesn’t sound very appealing. I assume a pipette used for this.

I have heard that using a little dish washing liquid in the water helps with this problem.

I’d like to hear a little more about how this is done.
Thank you

"meniscus" , a hibiscus is a sort of flower whose tea my mother is rather partial to!

I measure cases top overflow which means I fill them until the "bubble" of the water is proud of the case mouth but not quite overflowing. I then take a piece of toilet paper and using a torn edge wick off a tiny bit of water until the case mouth is utterly flat to the level of the water.

A tiny amount of dishwasher liquid will help break the surface tension down but it's not super critical with my method.

Make sure your cases are trimmed to standard length before you start measuring case capacities and do at least ten cases to get a half-way reliable mean.

quote:

"I measure cases top overflow which means I fill them until the "bubble" of the water is proud of the case mouth but not quite overflowing. I then take a piece of toilet paper and using a torn edge wick off a tiny bit of water until the case mouth is utterly flat to the level of the water.

A tiny amount of dishwasher liquid will help break the surface tension down but it's not super critical with my method.

Make sure your cases are trimmed to standard length before you start measuring case capacities and do at least ten cases to get a half-way reliable mean."

+1 on the above.

When I want to know the amount of actual available space-volume for powder, I make up a dummy cartridge, leaving the primer out with the bullet seated to the intended OAL. I then weigh the dummy cartridge and then use a needle syringe to fill the case with water through the primer hole and weigh that.

Hope you find this useful.

quote:

Originally posted by R D McMillan:

When I want to know the amount of actual available space-volume for powder, I make up a dummy cartridge, leaving the primer out with the bullet seated to the intended OAL. I then weigh the dummy cartridge and then use a needle syringe to fill the case with water through the primer hole and weigh that.Hope you find this useful.

What you are measuring, available powder space, seems more meaningful to me.
Similarly I try to measure capacity with the water at the neck shoulder junction.
If two cartridges are identical except for neck length their available powder capacity is the same if the bullets are seated to the neck shoulder junction or deeper. roger

Ya gotta be careful with Quickload water capacity.

Primer in case, cast trimmed to length, weigh case first, then fill to brimming, not with a bullet seated!! Weigh case with water, subtract the empty primed case weight. This is the number Quickload wants, the actual weight of the water that fills the primed case.

The bullet seating depth is taken into account by Quickload calculations when you input the bullet type and the COL.

I like to run another set of numbers with a fired, neck sized case vs a new unfired case.

quote:

"meniscus" , a hibiscus is a sort of flower whose tea my mother is rather partial to!

Sucks gettin older...

Anyway, thanks for the replies. Very interesting.

Case capacity should also be measured on a fired case that has not been sized.

Having horses at one time I got some syringes and needles from vet supply and that what I use to fill case with water. also use RCBS 1500 scale.

From the Quickload user's guide...

quote:

Maximum case capacity, overflow:
% Input, grains of water or cm3.
(The shipped database contains capacities for differing calibers and case makes. These are
only first-approximation values – obtain better data by measuring capacity of a fired case, see
text below).
It is imperative to accurately determine the average capacity for a given group of cases (brand
and lot) because case capacity differs substantially from lot-to-lot and brand-to-brand. This
measurement is easily done using a dry, empty fired case (with fired primer in place).
(For published loading data anywhere in magazines we often find case brand information
together with bullet, charge and primer data. This is tradition, but it makes no sense at all.
Cases are often "outsourced" manufactured, so in truth the manufacturer of one brand may
differ, and therefore the tools for drawing cases too).
For most RIFLE CALIBERS and other guns using peak pressures above 30,000 psi (2,000
bars): use a case fired in the specific gun you are working with. Do not resize the case before
making the capacity measurement.

For most PISTOL CALIBERS and other guns using peak pressures below 30,000 psi (2,000
bars): use a resized case.
After obtaining the weight of a dry empty case (with used primer in place), fill the case with cold
water. Eliminate any air bubbles and bring water even to end of case neck. Reweigh water-filled
case. Subtract dry weight from water-filled weight. This gives case capacity in grains of water,
which is the standard unit of measure.

Lots of variations in water volume capacity...trim length, powder residue in fired case, fired vs unfired cases, chamber size, case brand, etc...and how you deal with the primer pocket, i.e., tape it over, use fired primer or a bit of grease or pencil eraser.

Best way to do it is use a digital scale, do the primer pocket, set case on scale and tare it or "zero it out" as some folks say, fill the case with an eye dropper, eye drop bottle with the inside tube removed, syringe etc, then use tissue/towel to level out the water. This will give you a direct number without having to muck about with adding/subtracting.

I used to do 10 cases and average...now I just do one or two...this isn't brain surgery and there are all kinds of other variables that impact the velocity AND accuracy more than the "exact" volume...so don't sweat the small stuff...get close but don't go anal retentive.

QL, Load from a Disk and Powley computers are ONLY predictive programs NOT exact velocity dictators...a few grains more or less in the case volume box might only mean a few f/s in the velocity box and doesn't mean squat necessarily when compared to the chrono.

You get the approx velocity within plus or minus maybe 50 f/s from your chronograph. It might match the chrono, but it probably won't match to closely in many instances.

It really depends on just what you are doing with your rifle as to the value and effectiveness of doing the water weighing thing anyway...you can have 5-10 gr variation in case volume depending on case size over 100 cases. Unless you want to do all the other things required to benchrest prep a rifle AND ammo AND take advantage of all that work, then water weighing is just a waste of time.

For "normal" hunting accuracy just size, trim and load.

I might go through all the minutia and tune everything in sight, but that's because I require a higher level of accuracy than most...this is care of an early jump into benchresting...prior to that I was very happy with just getting my deer...sometimes I think I might have been much happier NOT getting into benchresting and having that "analthing" jump all over me....I wouldn't be forever measuring, weighing, sorting, everything I see, including ants and other bugs, food recipies, and carrying a laser rangefinder every where I go.

Luck

Again, very interesting.
Thanks.

what are we doing that requires such a precise measurement? Overhat you could determine using a fine ball powder? With 1/10th the mess.

The reason I use case capacity measured in H2O and not a specific powder is due to the fact that specific powder density can change from lot to lot and by the amount of humidity it has absorbed, in this way you may get one measurement one day and a different measurement months later. The other problem with using the powder method that I see is not knowing for sure how the powder settles in the case and if there are any air pockets within the powder charge. Also using the H2O method I can input that information into an Excel spreadsheet I made and it will tell me exactly how much case capacity is left when using a certain powder charge and bullet combo, kind like a poor mans QL.

ANY liquid will work just as well...the reason for using water has to do with it's well known properties and it is used by ALL predictive software programs.

It doesn't matter how fine a ball powder you use or how fine whatever powder you use, there will be air gaps between the granules and therefore it will give a false reading when compared to what is normally used. If you want to use ball powder for YOUR measurements,and it works for YOU then by all means use it, but all you are really doing, in fact, is weighing powder not measuring the volume of the case.

Remember Archimedes use water to measure the weight of the crown of the King of Syracuse, King Hieron, to see if the gold was pure or if the goldsmith had mixed something with the gold and made off with the difference in pure gold. Archimedes was actually measuring the volume of the crown...the same as we do to measure the volume of a case.

Luck

I guess what my real question is: what weapon(s) are you loading for that require such fine measurements? I know highly competitive bench rest shooters that use a scoop to measure their powder charges.

quote:

what weapon(s) are you loading for that require such fine measurements? I

It's not the weapons, but the software that requires the measurement.

The more accurate the inputs, the more accurate the predictions. One of the things QL attemps to predict is pressures, so any improvement in the predictions is a good thing.

Anelope Sniper hit it well...water weighing goes back a very long time, probably to soon after the first brass case was produced... Powley used it because it produced accurate volumes for his "calculators" and every software program I have or know of uses it to some extent...it is accurate, fairly precise, easy to do and pretty much the only highly accurate way to to "weigh" the volume of a case directly.

Measuring case volume has less to do with caliber/case water weights and more to do with case VOLUME uniformity.

NO case is precisely equal to another...as I said there are variations in EVERY aspect of this sport.

Measuring the case volume is one way to eliminate variation in internal volumes which means the powders gases are enclosed in a more uniform volume so, theoretically and in practice, you will achieve more uniform gas pressure on the bullet base, therefore more uniform velocities which translates into "Possibly" smaller groups. All the other variables impact as well.

The argument between scale weighing powder charges and "Volume" measuring powder charges, using a "scoop" or a highly accurate "Culver style" powder measure, throwing highly precise charges, has been going on for 50 years or more that I know of...with NO end in sight and each adherant going ballistic defending "Their" way of doing things...pretty much "busy-ness as usual".

I've done both and BOTH produce highly uniform velocities and BOTH have inherent "problems" that if addressed properly usually have less of an influence on group size than say the weather conditions at the range or the persons "bag technique" or thousands of other variables inherent in this game.

One basic problem, or result, is, we humans are individualistic with a herd mentality...we think the things WE do are the acceptions to the rule, yet tend to oversimplify, lock on to things we think are "the newest and greatest and unknown to any by ME", blow off what others think, yet still need the comfort of the herd. Not all bad, not all good.

Many people that are new to each type of shooting style usually have a steep learning curve to go through to get up to speed and many times get simplistic or place too much emphasis on the wrong area of emphasis and really totally miss where the real benefits are found, arguing over minutia that only applies in specialized areas and to specialized shooting...NO DISS OR FLAME INTENDED OR IMPLIED...again totally missing the real "good" information...

It ISN'T the fine measurement numbers that are important, it is what those measurements mean and what accrues from that knowledge and HOW that information/knowledge is applied.

If you want to shoot highly accurate weapons, no matter what the caliber, there are well known, well used, and well understood requirements that MUST be done...you learn to live with a caliper/mic almost permanently attached to one hand and your notebook in the other.

I like accurate rifles...any thing else is a waste of time and money. I have rifles from 17 cal to Rigby case sized 50 cal...they are ALL tuned and so is the ammo...they all can do bugholes, but mostly they all put 3-5 round into double the bullet OD group...all targets with bullets touching at the outside.

It takes only about 10% effort to achieve 90% of the accuracy potential...to get that last 10% potential it takes 90% MORE effort an "old timey" benchrest mentor kept banging into my mind. Over time I learned he was essentially right.

I can build a 3/4" - 1" rifle in a few days, load up some ammo and go shooting and take just about any game I point at out to 300 yds or slightly longer, but if I want that same rifle to do 1/2" or less groups and hit sageratz at 3-500 yds, I have to work fairly hard at tuning(blueprinting) the rifle and ammo...AND that means weight sorting brass(with and without water) bullets, powder, primers, trimming, neck turning, squaring case bases, working up a good and then shooting groups to eliminate "bad" brass...brass that tosses bullet outside the group. Every aspect of this process is highly argumentive as to HOW or the CORRECT WAY it should be done...but not much arguement over IF it SHOULD be done.

That "bad" brass might be excellent for "normal" shooting and might still produce 1" groups, but it is worthless if I want 1/2" groups.

It's YOUR choice as to how you go about doing your "thing", or if you even do it.

It should be obvious that it IS done at some level by ALL the good shooters...I guarantee if these things DIDN'T work they would be discarded quickly and never be heard again.
about

I don't water weight EVERY case but I do weight/sort EVERY CASE for EVERY rifle. You only have to do it once if you keep the cases sorted close enough...highly argumentive to say the least, but it has worked for me for all these years so I keep doing it.

Basically all you need to do is benchrest prep your cases...do a search, this subject has been run through the ringer going back way before the advent of the net...OR

Buy brass that is uniform to begin with like Lapua, Norma, RWS...I even check those brands and find a small level of variation that is or isn't detrimental to the level of accuracy I expect from my rifles.

Luck

The handy thing with water ......

" the reason for using water has to do with it's well known properties and it is used by ALL predictive software programs."

.......is it weighs 1 gram/cc so weight is a direct conversion to volume.
15.4324 grains /gram.
we weigh the case to more accurately determine the volume at typically 0.1 grain accuracy, which is 0.006cc accuracy.
much more accurate than trying to measure water volume directly.
Its a weight unit of water as a measure of volume.

The terminolgy is Equivalent Grains of water volume........a terminology unique to ballistics & not to be confused with any other volume or weight terminology........but its describing volume ( indirectly) not weight, in its specific use as a case volume measurement.

every other use of 'grains' in ballistics is describing a weight ( directly).

Excellent points, DenisB.

I had that bit of info about 1G/cc, one gram per cubic centimeter, written down to add into a response but I see now I missed.

Too often correct terminology gets left by the wayside or is assumed as "understood" or a 'given", but also many times the basis for extended hoohaws when it is NOT actually "understood".

"Grains of powder"(weight) and "powder grains"(individual particles) has always been a gigantic bugaboo to newbies going back a long time...plus converting from English units to Metric units or International Units can be a problem for many.

Luck