Case capacity: .30 Carbine v. .327 Fed Mag

[jski]

I searched the web hi and lo for the case capacity data on these 2 cartridges and got:

Wikipedia: 1.3640 cm3 (21.050 gr H2O)
Ammo Store: 0.92874 cm3 (14.3326 gr H2O)

Which are obviously at odds with one another.

For the .327 Fed Mag I got nothing, zero, the BIG goose egg.

Can anyone help?

 

[Captaingyro]

Wikipedia is correct for the .30 Carbine.

The math is pretty simple: the volume of a cylinder equals the area of the circle times the height, with the area being the familiar old Pi times R squared.

Converting the English measurements to metric yields a case diameter of .782 cm (.308 x 2.54) and the radius is half that, .391 cm.

Assuming a trim length of 1.290, I measured an average case depth of 1.115", or 2.83 cm.

Now we've got all the numbers. Plugging them into the formula yields a case volume of 1.359 cm3, very close to Wikipedia's number.

I don't have any .327 cases to measure the interior depth, but the math would be the same.

 

[Captaingyro]

A note to the above post: I realize that the .30 carbine case is slightly tapered. I assumed a perfect cylinder for the interior volume because the case walls get thicker toward the case head. In fact, the interior diameter may actually be a tiny bit larger at the bottom of the case. Wikipedia's number assumes an average interior diameter of .7834 cm instead of the .782 I used.

 

[Captaingyro]

A second note: looking at the Ammo Store's numbers carefully, they are giving the case capacity, not the total volume. The capacity is what's left after the bullet is seated.

 

[WestKentucky]

Getting good comparisons of internal space is good for cartridges that use similar powders... that's probably not the situation your dealing with here. Are you looking to match one to the other with handloads?