While reading a post over at DireKraken, I was reminded of the fix we used to handle firearms with a little more punch in d20 modern.
The complaint is generally that firearms aren’t deadly enough in d20 Modern, which is because the system uses the abstract D&D style hit points, where hit points represent the ability to avoid damage, not an actual measure of physical resistance to dying when hit.
Our quick fix was to increase the crit range of all firearms to 19-20 with a crit multiplier of x4. Specialist ammunitions can change this (increasing crit range with flechettes at the cost of a reduced crit multiplier).
This makes it so firearms are *generally* the same as they are in the base game, but when you get in a good shot, an average rifle will be dealing 36 damage instead of 18, with twice the chance of this happening per shot fired. It made the game a bit deadlier without the massive increase in lethality we ran into when playing with the Wounds & Vitality rules where a critical hit would instantly kill even high level characters.