Through my own experience i can tell you this,homing mean its will follow your enemy,ammo multiplier is like consume 1 but shoot the number of multiply for the type of ammo(for example of the Ripple,if you load it with blast mixture(or blast compound,i don't really remember that one well) it will shoot 4 projectiles while if you load it with silicon,it will fire 2 projectile at a time).About the blast radius,the radius around the impact spot is making an area equal to the area of about the numbers block in description.Other than that,knockback mean when enemy get hit,they have a percentage of getting push back when get hit,frag mean bullet will do a spread damage to enemy behind the enemy got hit(that what i think),incidary is enemy will take damage over time but it can re do the efect on your building so i don't recommend using pyronite as ammo and lastly,shock equal to enemy will got shock and stand still without doing anything at it spot