volume weighing brass

[lrgoodger]

Well, I've been volume weighing some 284 Lapua brass and found 3 gns difference in some cases so I'm assuming it has to make a difference at long range shooting a string.

If you are just weighing brass and not weighing the water it takes to fill them, then you are making a wrong assumption. A case that weighs 3 grains more than another can possibly have LESS internal volume than the other. This has been pointed out many times on this forum. Weighing brass by itself is a waste of time.

 

[rebel107]

No, Weighed trimmed to length brass first in a batch, then volume weighed. I'm not too concerned about .4gns difference when volume weighing but 2-3gns is too much.

 

[lrgoodger]

I've never done volume sorting. What is the volume of 3 grains of water and what percentage of total case volume is that?

 

[mikecr]

what percentage of total case volume is that?

Obviously this depends on your cartridge as formed in your local chamber. You can run the numbers in QL to find out what matters for you.

Folks, there is no shortcut for case volume. You measure it or not.
A chronograph can't give this info, because matched cases will still provide ES due to many other things. And it won't tell you neck tension, or bearing surface, or any other specific cause, until you figure out a way to actually isolate them in testing.
A chrono indicates the quality in combination.

I like the 21st Century plugs. In the past I've used a calibrated plastic golf tee, which worked really well.
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