Delve! Issue 2 Progress and Black Powder rules for old school games

I'm actively working on the second issue of Delve!  Unlike the first issue which was primarily an adventure, the second issue will be more or less segmented into articles more like a traditional zine.  The primary focus of issue two is the Town of Duschapel Downs.  Though there are other other articles and rules supplements for old school games.  Here's a my arquebus rules that I've been tinkering with.  These rules are hereby designated Open Gaming Content so feel free to use them if you want:

Black Powder Firearms Rules:  Arquebus

Part of the challenge of firearms in fantasy settings is that they could quickly overpower other combat options.  Quite often, many game masters completely forgo such weapons.   And there is the oft used rule that gun powder is inert on most fantasy worlds.  This can prove a bit troublesome for folks that want to emulate games set beyond the early and middle medieval period.  To that end, I’m setting forth the following rules for early black powder weapons such as the arquebus.  The arquebus, a firearm used primarily during the Renaissance period of our own world through the 17^th century. 

The arquebus was not as accurate as either the longbow or the crossbow, especially at long ranges.  However, it is more powerful than either, relying on the propulsion of the bullet by explosive gasses rather than mechanical tension or muscular action of the wielder.  In addition, the arquebus did not require a lifetime of training in order to become proficient in its use as did the longbow.  However, the arquebus required that the powder stays dry or it becomes inoperable.  It is all but impossible to operate an arquebus in the rain and under excessively humid conditions as the powder will not ignite. 

Base/Simplified Rules: 

Range increment 50 feet (-2 to hit per increment), 1/2 shot per round (1 shot every two rounds), encumbrance 10, damage 1d8+2.

Arquebuses have much better penetrating power than both long bows and crossbows.  At close range, they can penetrate most heavy armors quite easily (treat armor class as two steps worse – thus plate armor is treated as AC 5 vice AC 3 and studded leather is treated as AC 7 instead of AC 5).  In no case will this reduce the armor class to less than that of an unarmored man (AC 10).

Advanced/Additional Rules:

Advanced damage rules:  Firearms can cause grievous damage due not only to the projectile itself, but the force of the impact itself can cause severe trauma.  For the advanced damage rules, roll 1d10 base damage.  On a roll of 9 or 10, roll a d8 again for additional trauma damage and add the results (example:  a 9 is rolled and another d8 is rolled with a result of 5.  The 5 is rolled and added to the original 9 for 14 points of damage total).     

The sound from the explosion is quite loud (especially indoors and in confined spaces).  As such, anyone within 20’ must save versus paralyzation or be deafened.  The sound of the explosion has a 60% chance of causing spell casters to miscast magic (-5% for every level of the spell caster).  In addition, the smoke from the explosion is acrid and thick.  In a confined space it can obstruct vision.  If a black powder weapon is fired in a confined space, then treat as if there is 25% concealment (-1 AC) for all those within 10 feet.  This will increase if there is no ventilation at hand and shots are fired in successive rounds (50% concealment the next round, 75% the third round).  The smoke will dissipate after three rounds if no further shots are fired.

Early black powder weapons require frequent cleaning in order to avoid misfiring, jams, or even explosions.  The arquebus could be as dangerous to the wielder as it was to the enemy if it was not properly cared for.  On an attack roll of 1, the triggering mechanism causes the arquebus to explode causing 1d8 points of damage to the wielder.  In addition, the weapon is fouled at this point and required a minimum of 30 minutes of time to clean.