Firearm Proficient

You are skilled in the use of Firearms (Dungeon Master's Guide page 268), no longer phased by loud booming noise, the bright flash from the barrel, or the powerful recoil. 

• If you are not already proficient in using firearms, you gain proficiency with weapons of this type. 
• Improved Piercing: If the value rolled for damage for a firearm (which does piercing damage) is ‘8’ or above (without adding in modifiers) OR the damage reduces the target creature to 0 HP, the ammunition will completely pierce the original target. If there is another creature behind the target and also within 5ft, the shot will hit the creature dealing 1d6 piercing, no modifiers added. If a ‘6’ is rolled on this damage and there is another creature who fulfills the above conditions with respect to the second target, the shot will hit this creature dealing 1d4 piercing, no modifiers added.