Pistol Size & Weight
TFB TV (YouTube Channel) has a couple of terrific videos comparing 9mm and 380 pistols with regards to capacity vs size and weight. This is my modified version of their spreadsheet where I weighted capacity on a diminishing returns basis (see explanation video below). If you mouse over the upper right corner of the spreadsheets, you can open in Google Sheets.
Handguns - Rounds per size and weight
NEW (Beta) Volume analysis tabThanks to Blue Guns for supplying water displacement samples for this testing.
This tab replaces the height x width portion of the original spreadsheet with a total volume measurement (in cubic centimeters). The hypothesis is that there may be some gun manufacturers who put engineering effort into reducing overall volume, are not getting enough credit when looking at just height and width( for example the oval slide on the Walther PPQ vs blocky Glock).
Why "weighted rounds"? Look up "Marginal Utility".
Kinetic Energy per size & weight.
Handguns - Round Count Opportunity Cost
The average gunfight involves less than 4 rounds fired. Many threats are repelled by simply brandishing a firearm. So in my weighting I favor the first 3 rounds of capacity and then give diminishing value for each additional round thereafter as follows:
1 - 1
2 - 2
3 - 3
4 - 3.98
5 - 4.94
6 - 5.88
7 - 6.8
8 - 7.7
9 - 8.58
10 - 9.43
11 - 10.23
12 - 10.98
13 - 11.68
14 - 12.33
15 - 12.93
16 - 13.48
17 - 13.98
To put the size and weight values on approximately equal footing, I multiplied the Weighted Rounds/oz by three when calculating the Weighted Composite.