I use a fired case with a dead primer. Weigh the case, fill it with water to the top, wipe it dry and weigh it again and subtract.

What is the standard proceedure?

I deprime the case and seat a bullet then using a syringe (sp?) I fill the case thru the flash hole. This gives me the USABLE volume.

Your method is exactly what I use for case capacity. I also put a drop of detergent in the water to eliminate the meniscus. That is the standard for comparison of case capacity.

If you are looking for the capacity for the powder chamber, that is with a seated bullet, I do the same thing except I size the neck very slightly. File a slight trough in the bullet body to allow water to escape the case and weigh he bullet. Then seat the bullet slowly to the depth for the load with water up to the neck. You dry well, weigh, and subract the bullet and case weight.

The method that I use is to weigh a resized and trimmed case with a dead primer in it. Then I fill it with water from the tap and let it form a maniscus. (For comparison purposes, the maniscus is always the same.) Then I weigh my case again, and subtract first weight from second. That difference is the case capacity. This is one of the advantages of an electronic scale. Ku-dude

I use a fireformed, but resized case with the dead primer still intact. If no primer, then I seal off the primer pocket with modeling clay. Weigh the empty case. Then fill the case with distilled water using a syringe inserted from the mouth of the case. Add the water slowly to prevent trapping air bubbles. I allow a slight convex maniscus, then weigh the case again. The difference is the total case capacity. As far as usable capacity is concerned, it will differ from bullet to bullet as the seating depth changes. So to prevent having to do this over and over with each change in seating depth, I go for the total case capacity.
If I want to know usable case capacity for a given seating depth, I use the Bullet Displacement Calculator that's a free download at www.aement.com.
Regards,
Ed

[ 09-09-2002, 20:05: Message edited by: HockeyPuck ]

Why not use the fired case and not the sized case?

The fired case is the true volume of the chamber which is the final control and some load with neck sized cases.

I just brought this up to get a uniform system confirmed. Someone posted that they pour the water into the scale pan! I don't go along with that idea.

Pour the water out? You will be leaving some water on the inside of the case. You would not get a true capacity reading in that case.....

Leave it in the case and subtract the dry case weight...

Don Martin29,
Excellent point about the fired case being the final combustion chamber size. Very true. The reason I use a fireformed and resized case is because some energy is used to expand the case to the chamber size and the neck expands to release the bullet. If all possibilities were accounted for, the leade and throat of the chamber would also be tossed into the combustion chamber overall capacity.
My measurements are taken from several different case manufacturers and averaged to derive a value to include as a starting reference in our software. There is no substitute for measuring your own case capacity on a cartridge case fired in your own rifle. If you neck-size, and I would guess that most reloaders do, by all means go with your own numbers. Accuracy counts! And nothing and no one can give a value better than you can measure yourself.
Values given in manuals and software are just handy for comparison and "what if's", as long as they are values taken by the same method.
Then again, this is just my opinion.
Regards,
'puck

Then lets do it the way you do it. As I recall in a email that you average three cases which is also a good idea.