Case Prep for Water Capacity Weight?

[kcofohio]

Is there a correct (SAAMI) way to prep a case for weighting the water capacity? I did a search and didn't find any definite answer.
I took 4 ea. of 5 case brands. F.C., L.C., R-P, PMC, and Perfecta. Cases trim length 1.744" +/- .002". All cases are clean inside and inside of primer pockets were free of debris. Resized.
Each case has a spent primer, minus the anvil, seated.
I used distilled water and topped off case mouth level, no water dome.
The averages were as follows,
F.C. - 30.45 gr.
L.C. - 30.3 gr.
R-P - 30.45 gr.
PMC - 30.17 gr.
Perfecta - 29.5 gr.
I suspected that the Perfecta cases were less capacity, as I had pressure spike over the same load as L.C. cases.
Now when I look at the load data Nosler provides,
https://load-data.nosler.com/load-data/223-remington/
They show their case capacity at 27.4 gr.
So I'm wondering if my process is seriously flawed. Do they plug the flash hole? Would that be that much difference? Or is Nosler's case capacity really that much smaller.

 

[JFrank]

Could be’
I’ve never had the inclination to check capacity.
What are you trying to accomplish?

 

[Walkalong]

If I am loading .223 plinking loads with mixed cases, I just make sure my load is safe with heavier cases. I also look at powder level in every case, and scrap the occasional oddball where the powder is significantly higher in the case(way up in the neck), as I have so much range brass it isn’t worth it.

 

[kcofohio]

Could be’
I’ve never had the inclination to check capacity.
What are you trying to accomplish?

This exercise was twofold, to confirm my suspicions about the case capacity of the Perfecta brass (which all but a sample have since been converted to 300 Blk brass). And since Nosler provided case capacity and I have a couple of their .224" bullets. I wondered where to set my work up loads at.

 

[murf]

i just take a case and weigh it on a beam scale, then fill it with water from the sink and weigh it again on the beam scale. water tension will keep the water inside a rifle case when you lay it on the pan. i don't weigh pistol cases.

murf

 

[kcofohio]

If I am loading .223 plinking loads with mixed cases, I just make sure my load is safe with heavier cases. I also look at powder level in every case, and scrap the occasional oddball where the powder is significantly higher in the case(way up in the neck), as I have so much range brass it isn’t worth it.

I'm aiming to find if CFE223 or Tac worked best out of a 24" barrel with either 55 or 62 gr. Varmagedon bullet. But I may have to break down and use the remainder of the L.C. new brass I have.

 

[kcofohio]

i just take a case and weigh it on a beam scale, then fill it with water from the sink and weigh it again on the beam scale. water tension will keep the water inside a rifle case when you lay it on the pan. i don't weigh pistol cases.

murf

We have iron in the well water here and I wasn't sure if that would effect the weight. Probably not, but I thought distilled water would be a safe bet.

 

[murf]

i'm just comparing case weights between different brands, so the fluid used should not matter. just so the same fluid is used throughout the test.

oh, and i thoroughly dry out the cases before processing.

just reread the op. my way is not a saami way. i use a fired case and just pour water in it. i'm sure there is a more "exact" method, but mine works well enough for me.

luck,

murf

 

[markr6754]

If you want to eliminate the miniscule quantity of water filling the primer cup, insert the spent primer upside down. That said, I doubt it would make a difference. Also, to further confirm your suspicions re: Perfecta cases, take a measurement of the brass thickness of the case, with an inside (ball) micrometer. You could also use your caliper for measuring case inside depth to the flash hole.

I've seen the tools for plugging the primer pocket to make an exact reading, and never saw when or why I would ever need such a thing. Especially when a spent primer (or a sacrificial new primer) can accomplish the same task.

 

[Blue68f100]

I do it a little different.
Wet clean with pins, primers removed.
Sized, trimmed to all the same length.
I use a special plug to seal off the primer pocket. Believe I got it from Accurate Shooter?
I use water but add a little soap (409) to help breakup the surface tension.
Using a syringe to fill the cases while setting on the digital scales.
If the lighting is good you can get a good flat fill top.

I sort all my AR brass by mfg. LC by year. I did find that there are several years I can intermix. I found I could use the same charge if close and just tweak the OAL to dial the load into match.

 

[DocRock]

No, because the SAAMI spec is for case dimensions not capacity.

 

[JimKirk]

A small bit of soap breaks the surface tension .... tiny bit...

But you need rinse well before using ... sorta like pin cleaning ...

 

[kcofohio]

No, because the SAAMI spec is for case dimensions not capacity.

I wasn't sure if they did. I know they have the cartridge and chamber specs.
But with Nosler listing their case capacity. And the website AmmoGuide, which I have a membership with, list an estimated capacity for each cartridge casing. I was curious if there is a set standard for measurement.