Munitions Expert

You have spent a considerable amount of time tinkering and toiling away at experimental types of ammunition. You can create up 10 rounds of ammunition during a long rest, with materials costing 10 gold piece per 10 rounds. These can be bullets, arrows, crossbow bolts, or any other type of ammunition, subject to the DM's discretion. Futhermore, these magically crafted pieces of ammunition can either be made to simply more accurate, granting a +1 to damage and attack rolls, or apply some less-than-conventional methods to creating a new set of ammunition.

By applying these unconventional methods, such as using thermite to coat the ammunition, you can change its damage type to: Acid, Bludgeoning, Cold, Fire, Lightning, Necrotic, Piercing, Poison, Psychic, Radiant, Slashing or Thunder.

Furthermore, if the damage type chosen is not Bludgeoning, Piercing or Slashing, the ammunition deals an extra 1d4 damage.

You may also make an optional DC19 Check with the appropriate tools when creating your ammunition during a long rest. On a success, the ammunition's critical range is increased by 2 (18-20, by default). On a failure, the ammunition's critical failure range is increased by 2 (1-3, by default). You can increase this critical range by one, but increase the DC by 3 for each increase in critical range. 

Finally, the ammunition counts as magical for the purposes of overcoming resistances - However, will immediately lose its properties upon being fired.