It all depends. Long range and short range. Longbows or short bows , or crossbows or Javelins. 

Since we don't get technical to the material in the tip or if the ammo is made of wood or metal; velocity. Short range, bows would not penetrate leather, more than likely. A bow fired at long range, or into the sky at the right arc, will give it penetrating power. However, more than likely only Longbows and Crossbows at max power and velocity will have the ability to penetrate plate, if it can. Javelins probably won't have the power and velocity to penetrate plate unless loaded into some siege type weapon, but there isn't a problem for it to penetrate chainmail. 

This is my point of view with attempting to use realistic facts and logic. None of what I said is guaranteed correct for the roleplay standards nor what I say makes a difference in the roleplay due to my position. 

This is something Flooby will have to look into