Most don't explicitly effect mechanics, but instead shape what actions you can take with them, or what kind of consequences you might suffer on partial successes. Neither Laser or Plasma do what Penetrating does, but your armour-piercing .50 Magnum Millenium Eagle  can't cut a man-sized hole in a  door or panel the way a Laser beam might.<br/><br/>Your Rapid Fire assault rifle is less likely to leave half the squad you are shooting at alive, but more likely to cause collateral damage.<br/><br/>This video might help https://youtu.be/a4vTLeXam4Q<br/><br/>EDIT : And if you have someone you want to add to lore, just tell us! If we think it's a deal-breaker we'll sort out a comprimise, but this is a shared world, basically.