I think the issue with firearms is that the damage they do is already determined by physics, there's nothing inherently abstract about the damage a bullet will do. As most people tend to play characters with inhuman accuracy, they're never going to have their character miss, so the opponent has to have a defence available to block the bullet which is also incredibly difficult due to the speed it flies.

I wish that with projectiles you could just say 'well... they missed' or there was a system in place to take into account how even the most well trained soldier in the world still misses the majority of their shots unless they spend a long time calibrating (aka prepping.)

This is why I find weapons which aren't automatic fairer, for example the Clockwork Man and his Clockwork Pistol, or Isaac and his old fashioned flintlocks.