Question about ACTUAL case capacities...

"...reduce my commercial load by..." When loading milsurp cases the rule of thumb is to reduce the Start loads by 10% and work up. And don't worry about case weights, alloys, density's at 68F and all the rest.
 
I figured rubber meets the road and tested with ball powder to the top.

Tiny grains, clean sweep off.

I wrote it down someplace,e pretty tiny.

I just treat all brass the same, don't start at max, 5 to 10% lower than the lowest max (assumes I don't start lowest listed anyway)

I ran some data the other day on R17. Aliant does not show low loads, just say 10%,

Hornady that does list R176 and min to max, it was 16% spread.,
 
The head is a main cause of the weight differences.
Click to expand...

In the past case head weight had no effect on the diameter and or length of the powder column. I have R-P 30/06 cases with a case head thickness of .260" from the cup above the web to the case head. I also have thousands of surplus 30/06 cases with case head thickness of .200" from the cup above the web to the case head.

If we are in the habit if stacking? The case head protrudes from the chamber. The Mauser, in my neighborhood' has a case head protrusion of .110" with an unstacked .005" for clearance. For those that are keeping up that leaves .085 of the case in the chamber. My favorite case for heavy loads for the Mauser 98 is the Remington R-P case with the .260" case head thickness because of case head support. The most unimpressive case for the Mauser would be the 243 case mentioned in the illustration because .175" thick case head. Case head support on that case would be .060",

F. Guffey

And then there is that thing about; "What difference would it make?" It is possible to crush a case head with a heavy load, when the case head crushes there is less case head support and the case body is supported and locked to the chamber, there is a big chance that does not bother many reloaders but the one event I want to avoid is unsupported case head.
 
I am aware there are tolerances, I measure, I will not use a skinny headed A case, the worst cases I have found were Italian Kochahoney 303 cases. The case head thickness on those cases was .120". The only 303 rifles I had was one 1905 Ross and 4 P14s. And now the P14 are 30/06s, some kind of 8MM wildcats and 308 Norma Mag.

Then there were problems with the RCBS primer pocket swage. No one measured case head thickness; reloaders just went straight to swaging and rendering the primer pocket swages to scrap.

And then there is all of that ink wasted on case head space, again my SAAMI does not say the case has head space but if I was arrogant and was in the habit of making this stuff up I could find a lot of support.

F. Guffey
 
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