Leadbelcher

Ogres have long been on the receiving end of artillery fire, and they have grown to respect and admire its tremendous killing power. Indeed, such weapons are everything an Ogre admires; they are big, loud and have a proclivity to smash everything in front of them. As such they have taken to weirding them with their bare hands. Known as Leadbelchers, other races have learn their technique so long as they have the strength required.

Mobile Cannoneer

Starting when you choose this archetype at 3rd level, you gain a Leadbelcher cannon, gain proficiency with cannons and the Leadbelcher, allowing you to add your proficiency bonus to attacks made with them both.

Leadbelcher Cannon (Crafted/scavenged)
1d10 (+str mod) bludgeoning
Range 100/400, Loading, Heavy, Two-Handed, Siege Attacker.
300 lbs.
Any saving throws made vs effects of this weapon are against your Cannoneer DC which is equal to 8 + prof + Int mod.
When utilized as a melee weapon, the Leadbelcher deals 1d10+str Bludgeoning damage.
In order to reload your movement is restricted to 10 ft. of movement, this penalty is reduced to 15 ft. at level 5, 20ft. at level 7, 25ft. at lvl 10 and fully removed at lvl 15.

At level 5 you ignore the loading propriety of your Leadbelcher.
Your range while using the Leadbelcher when you reach higher levels increase by 50ft per level, reaching 150/600 at 5th level, 200/800 11th level, and 250/1000 at 20th level.

Hungry Gun

At 3rd level, you are able to channel your ability to feed almost anything into your cannon.
Spending a bonus action to reload allows you to grab item/s from your inventory or the battle field to fire as specialty ammunition. The item/s must equal 6lbs in weight. Using specialty ammunition decreases the base bludgeoning damage of the attack by haft.

The type of specialty ammunition added have different effects depending on what is added. All damage dice amounts increase by 1 at levels 5, 11, and 17. In addition during a long rest you are able to make specialty ammunition equal to your prof mod provided you have the materials. Discuss with your DM before hand about different materials.

Explosive. Highly volatile and dangerous, the target takes normal damage and any creature within 10 feet of the target must make a Dexterity saving throw vs. your Cannoneer DC. A creature takes 2d6 fire damage on a failed save, or half damage on a success.

Flashbang. When the target is hit, the target takes normal damage and any creature within 10 feet of the target must make a Dexterity saving throw vs. your Cannoneer DC. A creature is blinded and deafened on a failed save until the start of your next turn.

Smoke. Intended to give advancing armies cover and confuse enemies, Smoke shells explode into a 10 foot diameter cloud of smoke, which can be blown away by winds 10 miles per hour or stronger. Lasts for 10 minutes.

Poison. The Poison Shell creates a 10 foot diameter cloud of poisonous gas, which forces all creatures inside to make a Constitution save vs your Cannoneer DC or else take 1d6 Poison and be Poisoned for the next minute, they can make a save at the end of each of their turns. This cloud can be blown away by winds 10 miles per hour or stronger. Lasts for two rounds (12 seconds).

Chain Shot. The target must make a Dex saving throw vs. your Cannoneer DC or be restrained, they may use a action to make a Strength  check to brake free or have another creature use an action to do the same vs. your Cannoneer DC.

Shrapnel Shot.  Shrapnel Shells deal the normal damage and any creature within 5 feet of the target must make a Dexterity saving throw vs. your Cannoneer DC. A creature takes 2d6 piercing damage on a failed save, or half damage on a success. This also causes the area to become difficult terrain.

Corpse Shot. You know how to scare your enemies by firing their own allies back at them. Hit or miss all creatures within 10 feet must make a Wisdom save vs. your Cannoneer DC or become Frightened for one minute, they can make a save at the end of each of their turns. 

Specialty Shot

At level 7 you have learn how to modify your shots to give you different effects, you may either of these features equal to your proficiency bonus per short rest.

Koncussive Kaboom

On a hit, the target takes regular damage and must make a Strength Saving Throw vs. your Cannoneer DC or pushed back 5ft. times your proficiency bonus and be knocked prone, on a success they are only pushed back 10 ft. and not knocked prone. Any creature behind them must make a Dex save vs. your Cannoneer DC or be knocked prone.

Scrap Shot

After taking a bonus action to reload improvised ammunition, you use a action to fire a scrap shot in a 30ft cone. Targets in the cone must make a Dexterity Saving Throw vs. your Cannoneer DC. Upon a failed save the target take d10 Piercing damage per your proficiency mod, half as much on a success. This damage does not suffer the penalty of Hungry Gun. (ie prof mod 3 = 3d10)

Get in There!

Starting at lvl 7 when you finish a target that is medium sized or smaller with a melee attack from your Leadbelcher, you may reload using the coupe as a item interaction. Your next ranged attack counts as a specialty ammunition.

The Big One

At 10th Level you are experienced enough with black powder to combine with your ammunition, not just the cannon itself. As an action you target an area with a radius equal 10 ft. times the number of extra attacks you can make within your Leadbelcher's attack range. All creatures within must make a Dex save vs. your Cannoneer DC or take 2d10 bludgeoning damage and 2d6 fire damage per extra attack you can make, haft damage on a successful save. You may use this feature up to your Intelligence modifier per long rest.

Fitting it all in

You know how much your gun can fit with maybe a bit of room on top. Starting lvl 10 your able to combine 2 specialty ammunition effects together in one attack.

This effect increases to 3 at lvl 15 and 4 at lvl 18.

One for All

At 15th level, you've become the master of artillery, when you hit a target with an attack, all targets within 10 ft. around it take haft as much bludgeoning damage.

You are proficient enough with your weapon and it's ammunition to improvise from anything you find. You no longer suffer the hafted damage from specialty ammunition.

All the world into the gun

You've learned all that works with your leadbelcher and then some. You no longer require a bonus action to load your leadbelcher with specialty ammunition, your base damage increases to 2d10, and you can fit parts of large creatures into your leadbelcher.