Percentile system questions

[stobetex]

The game's about biker dominatrixes with improvised firearms exploring the ancient ruins exposed by Antarctica melting. But enough about that.

There's a percentile skill that tells the player how good she is with bows, throwing knives and guns (looking for a noun like Markswoman or Ranger, any suggestions?)? Let's say she's at 67%. Now the shoddy PVC-pipe shotgun has a 12% backfiring chance. She's good with guns, so she can repair and maintain them. So how do I make a check if the gun explodes in her hands, her skill has to lower the chance somehow, right?

Also, the same skill determines who shoots first. So how do I pit her 67% against a hostile looter's 45%? He's got a hangover too so there's some kind of modifier there that's good for our latex-clad heroine now.

Let's say she fires first. Another roll to see if it's a hit (modifiers). But how do I use Markswoman to determine how good the hit was?

[jqavins]

The game's about biker dominatrixes with improvised firearms exploring the ancient ruins exposed by Antarctica melting. But enough about that.

No it isn't! How could one sentence ever be enough about biker dominatrices with guns?!!

There's a percentile skill that tells the player how good she is with bows, throwing knives and guns (looking for a noun like Markswoman or Ranger, any suggestions?)?

Sharpshooter.

Let's say she's at 67%. Now the shoddy PVC-pipe shotgun has a 12% backfiring chance. She's good with guns, so she can repair and maintain them.

Are you sure you want gun repair to fall under the same skill as gun shooting? I'd make it a separate Gunsmith skill. But that's neither here nor there as far as the mechanics go.

[DISCLAIMER]What follows is a series of suggestions to be taken or left for what they're worth, and not based on any particular expertise in this area.[/DISCLAIMER]

So how do I make a check if the gun explodes in her hands, her skill has to lower the chance somehow, right?

Make gun maintenance a different action from shooting (whether or not it's a different skill). For each type of gun assign a base chance of unplanned rapid disassembly; for a shotgun made out of PVC it's probably pretty darn high; 12% sounds crazy low, but I digress. Wear and tear increases the chance, but a successful maintenance roll against a rather low DC prevents that. A successful maintenance roll against a moderate DC can lower it by a notch, back to the original, like new value after enough successes. Probably the DC should get worse as the damage progresses (it's harder to even to make headway against major damage than minor) but not by too much. A success against a considerably harder DC can lower the chance to better than new, but only a notch or two.

All this is done before the trigger is pulled, and at shootin' time the Sharpshooter (or Gunsmith) skill does not enter into the result, only the gun's condition.

Also, the same skill determines who shoots first. So how do I pit her 67% against a hostile looter's 45%? He's got a hangover too so there's some kind of modifier there that's good for our latex-clad heroine now.

Aw, c'mon; leather-clad! (All right, maybe she's just into latex; to each her own.)

Anyway, a simple contest. Each combatant rolls a d% and adds his/her skill and bonuses/penalties (and a Dex or other speed bonus?). The higher total wins. Easy as pie.

Let's say she fires first. Another roll to see if it's a hit (modifiers). But how do I use Markswoman to determine how good the hit was?

Use the Sharpshooter skill itself as either the damage, or as a damage bonus on top of a damage die. Depending on the scale of things (i.e. how many hit points people generally have) you probably want to divide the skill by some number, so Sharpshooter/10, or Sharpshooter/20, or Sharpshooter/4, depending on the scale.