I had this crazy nutso idea floating around for a while that was very gun-heavy when it came to combat, using a very simplistic damage model that took the math equation Dam=D*L/10+B where D is the diameter of a bullet in millimeters, L is the length of its case also in mm, and B being the gun's barrel length in inches. So a standard 9x19mm MP5 submachine gun with an 8.9-inch barrel would deal 26 damage per bullet (out of, on average, 100 health points), based on 9x19/10 being 17.1, plus the barrel adding up the remainder. Or an AKM hitting with 46 damage, if 7.62x39/10 is around 29.7 + 16.3 = 46. On the one hand, this leads to such imbalances as 9mm subcompact pistols being stereotypically underpowered. On the other hand, pretty much everything else is shown that guns are indeed deadly devices that are not to be fucked around with when dilly-dallying about.

That being said, my original idea was for either a dystopian America with resistance cells fighting a tyrannical US gov't or some sort of post-apocalyptic... *thing.* I'm not quite sure what even an alpha would look like, since I was mostly focused on thinking out the mechanics for accuracy, encumberment, environmental effects, and suchlike.