the gunslinger

Nice attempt. You have some good ideas here but I think you need some refinement for sure. I quickly want to validate your decision to have six shooters but no repeating rifles as the six shooters in the picture looked to be something like colt navies which were Involved six shooters… At the time these pistols were used, there were only musket style rifles for the most part so I wanted to address that criticism that you received real quick. I also noticed that you received a criticism for the grip providing a +2 but the archery fighting style does the same thing and this class doesn't have fighting styles. By itself, this is an overpowered at all but when paired with a fighting style, that is a +4 which is really extreme. The only way it can work is if you make it exclusive of fighting styles somehow.

The main thing that attracted me to this class was the picture which has a gunslinger with two fists full of gun! Unfortunately, there doesn't seem to be any way to do this in the class you wrote as...See more standard dual wielding requires to melee weapons with the light property. It would've been nice to have a weapon attachment or a deed that allowed you to wield a pair of revolvers at the same time.

This is an interesting draft of this class. A few questions: why does the gunslinger add Int instead of dex to damage? The bayonet does as much damage as a short sword when it is probably closer in size to a dagger, and the serrated bayonet is the most damaging dex based melee weapon in the game. My next question is why are there revolvers but only muskets? Why aren't there repeating rifles?

Dead eye should be treated like battle master maneuvers and dice. The Save DC should also be treated like standard class DC or 8 + Ability (most likely dex) + Proficiency. So expand the Dead eye list and say a character can get 2 maneuvers at level 1, and can add an additional one at level 3, 7, 10, 15, and 18th. The Drawfire should probably be treated more like the Compelled Dual spell - Wis ST, on fail, enemy has dis adv on all attacks against anyone else.

The reloading time on the guns makes them slower than crossbows. You should just adopt the standard terms for everything used in the PHB. So...See more the guns should have the ranged and loading property, and some of them should have the two handed property. There is no reason to reinvent the wheel to define the weapon's attributes.

The gun attachments are a bit overpowered. A grip adds a +2 to attack for almost no cost.

I'd honestly take a look at the original artificer from Unearthed Arcana: https://media.wizards.com/2016/dnd/downloads/1_UA_Artificer_20170109.pdf

Specifically look at the Gunsmith. While this build didn't make it into the final build of the artificer in the Eberon book, it is a good jumping off point.

Your class is a valiant effort but it needs some work to bring it into line with the standard 5e level progression, mechanics, and nomenclature. A good exercise for really figuring out this class is to ask the question: is there a functional difference between a gun and say firebolt or eldritch blast other than that one is a weapon and the others are spells? Other than getting to use firearms, what thing does this class do that isn't covered by another class?