Orphan Mechanics: Muskets
I've been working with a friend on a project off and on and one of the things I've put a little thought into is the idea of coming up with a neat and cool mechanic for early musket fire to differentiate them from regular weapons at the time. Even early muskets were effective against cheap armor, but the real good stuff had a chance to deflect or slow down a shot and I am casting around for a mechanic to reflect some of this.
One game that did something I like with this is The Nightmares Underneath, which uses a standard "roll a d20, add your attack bonus, and compare it to Armor Class" method for most attacks. Firearms, however, are simply resolved by rolling a d20 and trying to get under your Dexterity value, which is generated using a roll-3d6 method. This makes these new pieces of technology frighteningly easy to learn for the masses in a way I quite like; part of the reason firearms were adopted quickly for battlefield use over the tried-and-true pointed stick was due to how easy they were to learn and how little physical ability the user needed in order to kill the enemy at range compared to bows and crossbows. At the same time, metallurgy was picking up to the point where late medieval/early modern armor was quite complex; think of D&D's "full plate" armor for the kind of protection someone wealthy might be tromping around in. So, I'm casting around for a mechanic that represents this weird period in history where well-made armor can stand up against some easy-to-use guns.
Here's one of my failures.
3d6 Roll Under Armor Class And Use The Rest
The system I'm working with uses descending armor class (lower AC = more protection). One idea I had was to ignore regular to-hit rolls for muskets and instead roll 3d6. At least one d6 must be under the target's AC to hit; drop this die and apply the rest as damage.
I hope you can see the logic there. Lower AC means you have a better chance of a bullet just deflecting, though if they penetrate they tend to deal good damage. It makes some intuitive sense, even if it is a little hostile to a player; I can absolutely imagine several of my friends getting really mad at me trying to remember this. The problem is that it swings the odds to in favor of firearms that it's no longer fun or interesting, not to mention a little out of step with simulation.
This means that against someone with leather armor or worse a gun always hits every single time and does on average 8.5 points of damage. Leaving aside the question of accuracy for the time being, this is more than twice as many hit points as an average person has; a single volley from massed musketeers would leave any nation short an whole generation of men. Every encounter would turn into Somme-level casualties instantly. Armored fighters don't fare much better, with someone wearing heavy plate (AC 2) taking a hit 42% of the time and suffering an average 7.4 damage in the process. While I do like the "all or nothing" feel of a musket shot here when one takes the hit chance into account the average per round is 3.1 damage.
Even changing the roll to 2d6 doesn't fare much better with those wearing leather armor or worse suffering from 4.5 damage per shot and someone in heavy plate taking 3.7 damage about 31% of the time.
In Conclusion
There's definitely something here but not for this game. Maybe in a naval wargame or similar; I could see how you might change the dice thrown for different calibers of shells or something. I also like that it's easier for someone with less training to inflict damage compared to the linear odds of a regular weapon, but I'd like to see a curve that takes into account the difference a trained fighter might make in comparison. As it stands now, the damage returned is just too high and I don't see it working.