Case capacity / H20 fill

Dave_45 · Apr 27, 2026

Does anyone use the seated bullet method of

Seating a bullet in a case and weighing that dry and then filling via flash hole with blunt syringe and weighing the file case to get an accurate H20 capacity ?

Or do people use the fired case only and fill with water ?

pendle · Apr 27, 2026

Hi @Dave_45 do you still have the trigger for tikka artic for sale. Will it fit the t3
Have Dm you.

jb1 · Apr 27, 2026

Dave_45 said:
Does anyone use the seated bullet method of

Seating a bullet in a case and weighing that dry and then filling via flash hole with blunt syringe and weighing the file case to get an accurate H20 capacity ?

Or do people use the fired case only and fill with water ?

I would use a spent primer.

Eric the Red · Apr 27, 2026

Most calcs want case capacity to overflow - so spent primer - weigh - fill til meniscus shows - reweigh - calculate difference. Quickload for example then calculates the revised volume according to the bullet you choose and the respective seating depth.
Has worked very well for me.

MTheaded but happy · Apr 27, 2026

As above for GRT ^^^^^^

JamesH · Tuesday at 6:09 PM

P-Max does it the other way around with a seated bullet and fill through base. I’m sure either get good results just don’t mix and match.

Malxwal · Tuesday at 6:15 PM

JamesH said:
P-Max does it the other way around with a seated bullet and fill through base. I’m sure either get good results just don’t mix and match.

Sounds like a right faff, and a recipe for trapped air ?

Lateral · Tuesday at 6:17 PM

You can drive yourself mad, because cases can vary by several %. Loading for a new chambering, or new brass, generally Lapua, or Norma, I measure the H20 primer in, of at least 5 cases, and then take an average.

MTheaded but happy · Tuesday at 7:36 PM

GRT requires it to be a fireformed case .

Lateral · Wednesday at 1:46 AM

MTheaded but happy said:
GRT requires it to be a fireformed case .

I'm aware of fireform case being suggested, but I find this confusing, "unless" you're only neck sizing, otherwise the volume is reduced when full length sized ?

I think consistency is more important, and the H2O just gives a starting point ?

25 Sharps · Wednesday at 7:06 AM

Lateral said:
I'm aware of fireform case being suggested, but I find this confusing, "unless" you're only neck sizing, otherwise the volume is reduced when full length sized ?

I think consistency is more important, and the H2O just gives a starting point ?

It’s only reduced momentarily, after a milisecond or 2 on firing it has expanded to fill the chamber and then it can’t expand any more so this is the volume you are really dealing with.

Lateral · Wednesday at 8:09 AM

25 Sharps said:
It’s only reduced momentarily, after a milisecond or 2 on firing it has expanded to fill the chamber and then it can’t expand any more so this is the volume you are really dealing with.

I'm not suggesting that it doesn't make a difference, but I'd love to see the results from a comparative test.

25 Sharps · Wednesday at 9:09 AM

Lateral said:
I'm not suggesting that it doesn't make a difference, but I'd love to see the results from a comparative test.

Comparative modelling or on paper/ over the chrono.

dropmdead · Wednesday at 10:49 AM

I would recommend using fired case and primer method to measure case volume. There are other methods too to help refine cases, but for longer range deer etc i would bother too far in terms being excessively pedantic. If for long range steel/paper, then you can refine everything to have minimal SD/ES.
Feel free to ping me a text message if you want to discuss further your ideas.

Lateral · Wednesday at 12:50 PM

25 Sharps said:
Comparative modelling or on paper/ over the chrono.

Over a chronograph, and POI shift.

I think whichever way you measure/ load, consistency is the most important

timbrayford · Wednesday at 1:23 PM

For the 1000 yard/meters competition stuff I can understand taking the trouble but for clover leaf at 100 it seems to be way too much bother.

25 Sharps · Wednesday at 3:21 PM

Lateral said:
Over a chronograph, and POI shift.

I think whichever way you measure/ load, consistency is the most important

That’s really a test of FL sizing Vs Neck sizing, not modelling input parameters.

Case capacity / H20 fill

Dave_45

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pendle

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jb1

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Eric the Red

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MTheaded but happy

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JamesH

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Malxwal

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Lateral

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MTheaded but happy

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Lateral

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25 Sharps

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Lateral

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25 Sharps

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dropmdead

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Lateral

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timbrayford

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25 Sharps

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