Not every engagement can be won with gunpowder alone. These riflers have thus focused their aim towards the arcane side, rather than the technical side.

Arcane Knack

You have studied the arcane and understand it in a manner few can match. . .

At 3rd level, You become proficient in Arcana, you may also learn one wizard cantrip of your choice.

Arcane Riflemanship

Upon choosing this archetype at 3rd level, you gain proficiency with Tinker’s Tools. You may use them to modify and repair damaged arcane guns, or even draft and create new ones (DM’s discretion). Some extremely experimental and intricate arcane guns are only available through crafting.

Arcane Properties

Arcane guns have their own unique properties. Their nature is highly volatile and uncertain, thus there's a lot to improve. But, when things can go catastrophically badly, they can also go gloriously well.

Reload. The weapon can be fired a number of times equal to its Reload score before you must spend or 1 action to reload. You must have one free hand to reload a firearm.

Volatile Eruption. Whenever you roll an attack with your arcane gun, you have a chance for the rune to erupt in the cylinder. Some weapons are more volatile than others. When you roll below eruption, the rune explodes in the cylinder, breaking the gun. To repair your arcane gun, you must make a successful Tinker’s Tools check (DC equal to 8 + eruption score). If your check fails, the gun is broken and must be mended out of combat at a quarter of the cost of the firearm. Creatures who use an arcane gun without being proficient increase the weapon’s eruption score by 1.

Name	Cost	Ammo (20)	Damage	Weight	Range	Properties
Cuckoo Pistol (Revolver, upgradable)	50g	3g	1d8 piercing	1 lb.	(40/160)	Light, reload 1, Eruption 1
4 rounder (Revolver, upgradable)	250g	5g	1d10 piercing	3 lb.	(60/240)	Reload 4, Eruption 1
Rifle (Upgradable)	500g	7g	1d12 piercing	10 lb.	(120/480)	Two-handed, reload 1, Eruption 2
Peacemaker (Revolver, upgradable)	350g	5g	1d10 piercing	5 lb.	(80/320)	Reload 6, Eruption 2
One Upper (Upgradable)	Crafted	11g	2d12 piercing	25 lb.	(200/800)	Two-handed, Eruption 3, reload 1

Upgradable Components. You can choose to upgrade your guns by constructing components.  To upgrade your gun you must buy the components required, the price for them is listed in the table below. To apply the components you must make a tinker's tools (int) check of DC 15. On a failure, you lose your materials for the component, and if you roll a natural one, your arcane gun breaks as well during the process.

 

Name	Cost	Properties
Improved Sight (Rifle, One Upper)	150g	Range +30
Cylinder Magazine (Rifle)	250g	Reload +5
Improved Grip (Rifle, revolver)	50g	Range +10
Rifle Strap (Rifle)	10g	You can stow the rifle, then draw another arcane gun as a single object interaction on your turn.
Improved Hammer (Any gun)	600g	+1 uses of Arcane Runes.
Quick Mag (Peacemaker, Rifle)	1000g	You can load your gun as a bonus action.
Bayonet (Rifle and One Upper)	100g	You can use your action to use your bayonet to attack. This attack deals 1d6+str piercing damage, and uses your str for attacks you make with it. It is considered magical. Though you can make a non-magical variant at 1/3rd of the cost.

 

Arcane Rune Smithing

Ammunition Properties: Your weaponry channels the weave using a special form of ammunition known as runes. Their nature is entirely magical. Your attacks with this ammunition are considered magical. Your runes are also subject to any effect that prevents magical energy from functioning, such as an antimagic field.

Special runes: At 3rd level,  you can choose to learn 3 types of special runes, which you can change during long rest. These runes leave marks on impact, you can activate one mark to impose special effects on their target.
Upon activating a rune, your attack deals extra damage appropriate to your rune damage die which at 3rd level is a d4.The damage die scales to a d6 upon reaching 7th level, d8 at 10th, d10 at 15th and a d12 at 18th level. Please note, that your rune deals the damage type appropriate to the rune you decide to use for the attack. For example, if you choose to use the acid rune, your rune damage die deals acid damage.

At 3rd level, you can use these runes 3 times, regaining the uses after taking a long or short rest. You gain an additional use upon at 7th, 10th, 15th and 18th level.

You use your intelligence spell save DC to dictate the DC for these effects (8+proficiency+intelligence modifier). You can only use one rune per attack action.

Special Runes

After you make hit a ranged attack with your Arcane firearm, it leaves behind a mark which you can activate to deal more damage proper your special rune damage die.

The runes are presented in alphabetical order:

Acid Rune

When you activate this rune, if the creature is wearing metal armor, they then must make a Dexterity saving throw. On a failure, they suffer -2 to their AC, if they are wearing armor. Once they have suffered -4 to their AC, their armor is destroyed.

Cold Rune

When you activate this rune, the creature must succeed in a Strength saving throw, or have their speed be halved until the end of their next turn. If the target is immune to cold, it still has to make the saving throw. On a failure, it is still subject to the effect.

Fire Rune

When you activate this rune,  the creature must succeed in a Dexterity saving throw, or be set ablaze for 1 minute. Taking 2d4 of fire damage at the start of each of their turns. It takes an action to douse these flames. If a creature is immune to fire, they can't be set ablaze.

Force Rune

When you activate this rune, both the creature and any additional creatures within 10 ft. of them take damage equal to your rune damage die. The target then must succeed in a Strength saving throw, or be knocked back 10 ft. If the target is immune to force damage, it doesn't take any damage but is still subject to knock back if it fails the save.

Lightning Rune

When you activate this rune, the creature must make a Constitution saving throw. On a failure, they are unable to take reactions until the start of their next turn. If the creature is immune to lightning damage, it is immune to this effect.

Necrotic Rune

When you activate this rune, the creature must make a Constitution saving throw. On a failure, they take extra 1d6 necrotic damage, in addition  you gain temporary hit points equal to the damage dealt by your special rune damage die. If the target is immune to necrotic, it’s immune to this effect and you don’t gain any temporary hit points.

Poison Rune

When you activate this rune, the creature must make a Constitution saving throw. On a failure, the target takes 2d6 extra poison damage, and is poisoned for 1 minute. They can retry the saving throw at the end of each of their turns. If the target is immune to poison, it is immune to this effect.

Radiant Rune

When you activate this rune, the creature must make a Constitution saving throw. On a failure, the creature becomes blinded for 1 minute. The creature can retry their saving throw at the end of each of its turns.

Thunder Rune

When you activate this rune, the creature and any additional creature within 10 ft. of them must make a Constitution saving throw. On a failure, they become stunned for until the end of their next turn.

Eye For Weakness

When you reach 7th level, you gain an eye for a creature's weaknesses. After watching a creature for 1 minute, you become aware of their damage resistances, immunities and vulnerabilities.

Furthermore, you can add your Intelligence modifier to your initiative roll and your ranged attack rolls.

Suppressive Fire

At 10th level, when you hit a creature with your arcane gun, you may spend one of your rune usages to mark it. When marked in this way, the creature provokes an attack of opportunity from you every time it moves.

Arcane Vigor

Once you reach 15th level, you can use your bonus action to regain uses of arcane runes equal to your intelligence modifier.

You regain the use of this ability after a long rest.

Arcane Deadshot

At 18th level, you may use your action to activate you gain the following benefits for 1 minute:

• If you kill a creature with an Arcane Firearm, you may use your bonus action to make an additional ranged attack against any creature within range.
  
• Anytime a creature moves within 30ft of you, you may use your reaction to make an attack against them
• If you kill a creature with an Arcane Firearm, your reload property for that weapon resets.

Once you use this feature, you cannot use it again until you finish a long rest