The M16 has trouble targeting downed zombies. There is a delay when you shoot at one that is totally prone (i.e., not trying to get up or crawling). It's also very difficult to get a hit or kill shot on a downed zombie until it's at least starting to get up.   Build is 42.7.0 I'm using a lvl 8 firearms character I don't use the targeting highlighter I've mostly leveled using a JS-2000, a 1911, and an M36--none of these weapons have the same bug once you get used to using them   (edited to add version)

"Attitude: Stressed"   Understatement of the century.

Smaller incidental details like weapon weight can have a huge impact on your perception of a character's endurance.  Maybe you were using heavier weapons with your female characters and ended up with something lighter for the male character, causing the former to get fatigued faster than the latter?  It's hard to analyze without seeing every step of the run.   Personally I do think there should be some sex-based performance differences, where males could have a higher strength and fitness curve but females could have better pain tolerance and infection resistance and there could be a few sex-based bonuses for different skills.  I get why they don't want to implement something like that but it wouldn't be bad to have as a sandbox / realism option.

Lol  

Redefining the meaning of blacklights!