9mm Case Volume?

[rdtompki]

I'm loading current 124gr LRN (coated) using WSF. Since it's the only powder I have I'm trying to get as smart as possible. I'm not going to experiment with loads beyond what is available on Hodgdon, but it's useful, for example, to understand how much powder it takes to fill a case.

I've seen multiple sources state a .86 ml (=cc) case volume. When I calculate the case volume excluding the base I get ~1.2ml. I'm using SAAMI specs, but I'm not taking the wall thickness into account which probably explains the difference.

Understand the wall thickness varies by manufacturer, but what's a good approximate value? Using the .86ml case volume a full case would contain 10.7gr of WSF based on the WSF density obtained from a Lee table.

 

[rcmodel]

but it's useful, for example, to understand how much powder it takes to fill a case.

How is it useful?

10.7 grains WSF is about 2 times what it would take to blow up any 9mm pistol!

Hodgdon lists 124 grain lead bullet data as:
Start = 4.0.
Max = 4.7.

Thats all you need to know to make safe loads.

rc

 

[Gadawg88]

Why can't you just fill the case with powder and then weigh the powder, or am I not understanding what you are trying to do. Like RC said, how is it going to help?

 

[Jlr2267]

Fill the case w/water...weigh the water (in grams)...that is also the volume in CC.

Not sure that is useful info however.

 

[Jim Watson]

You are pushing powder density data from Lee way beyond its useful range of accuracy.
Heck, I think LEE pushes their own powder density (actually the inverse of density) too far.

Do you have a powder scale? Why not?

 

[PhilMc]

Why?
I'm with Rcmodel load to published specs and be safe.

 

[Walkalong]

Almost all powders suitable to load 9MM will fill the case well, well enough not too matter. Follow the load data and quit worrying about it.

 

[moxie]

If you are using Lee data, do yourself a favor and throw it away. They just cherry pick data from other sources.

Stick with reliable concerns that do their own load workups and have their own ballistics labs. Go with Speer, Lyman, Sierra and Hornady. Good websites include Hodgdon/Winchester and Alliant. Nosler.

 

[rdtompki]

Do you have a powder scale? Why not?

Of course I have a powder scale. I have two powder scales and I have no intention of loading at or above the Hodgdon max. for LRN bullets. I'm accumulating several powder drops to verify a load and using both a powder cop and visual inspection during loading.
'
I simply came across the case volume figure and want to understand why it differs from a calculation of case volume. It probably relates to wall thickness.

 

[JamieC]

If you are using Lee data, do yourself a favor and throw it away. They just cherry pick data from other sources.

Stick with reliable concerns that do their own load workups and have their own ballistics labs. Go with Speer, Lyman, Sierra and Hornady. Good websites include Hodgdon/Winchester and Alliant. Nosler.

What is wrong with data from Lee? Haven't they been doing this awhile? Are the sources they are "cherry picking" from no good?

 

[Reloadron]

Of course I have a powder scale. I have two powder scales and I have no intention of loading at or above the Hodgdon max. for LRN bullets. I'm accumulating several powder drops to verify a load and using both a powder cop and visual inspection during loading.
'
I simply came across the case volume figure and want to understand why it differs from a calculation of case volume. It probably relates to wall thickness.

That would be about it. Nothing wrong with satisfying your curiosity. I have a 9mm case laying here. Not sure where it came from since I haven't shot or loaded 9mm in years. The case happens to be an A-Merc case. So I weighed the case and it weighed about 61.7 grains. I filled the case with some common tap water (not about to go looking for pure distilled water) and it weighs 74.6 grains. I think I can safely say the water weighs 12.9 grains which is about .83591 grams or let's call it .84 grams or since 1.0 gram = 1.0 cc of volume we can say 0.84 cc. Another case on another day will likely give different numbers, close but different. Case length, case wall thickness and other small variables come into play.

The case, however, will not hold that much powder anyway because once I shove a bullet down in that case you can pretty much figure my numbers are now as useless as teats on a bull. My seated bullet will take away a good chunk on my volume.

All things considered yes, it is a collection of variables that cause the differences in the calculations.


Just My Take....
Ron

 

[Jesse Heywood]

What is wrong with data from Lee? Haven't they been doing this awhile? Are the sources they are "cherry picking" from no good?

Some of Lee's data is good, but some is outdated. SAAMI has changed some things due to advances in the science. And Mr. Lee has played favorites with manufacturers in the past. So his data should be checked against other sources. I would like to see him show references to the original data, but that's a pipe dream.

 

[thefish]

, but it's useful, for example, to understand how much powder it takes to fill a case.

I too don't understand how it would be useful, but if you want to know how much WSF it takes to fill a case, why not fill the case, then dump the powder onto the scale?

I guess I don't understand the question.