angel,
Hand-loaders are more interested in the capacity of cases when working up pressures, not the case itself. You are weighing different brands of cases and they will vary slightly, but you cannot assume much from the differences.
With capacity, size a case and seal the primer hole somehow. A spent primer works. Weigh the case. Then fill the case to the mouth with water and weigh again. The difference between empty and full is the capacity or volume in water. Be careful to get rid of any bubbles and don't have too proud a meniscus at the mouth.
If you have Quickload you can replace the default case capacity (35.99 grains H2O) with your converted brass. See how the change in volume affects predicted pressures.
Hand-loaders are more interested in the capacity of cases when working up pressures, not the case itself. You are weighing different brands of cases and they will vary slightly, but you cannot assume much from the differences.
With capacity, size a case and seal the primer hole somehow. A spent primer works. Weigh the case. Then fill the case to the mouth with water and weigh again. The difference between empty and full is the capacity or volume in water. Be careful to get rid of any bubbles and don't have too proud a meniscus at the mouth.
If you have Quickload you can replace the default case capacity (35.99 grains H2O) with your converted brass. See how the change in volume affects predicted pressures.