So, of COURSE, the Really Wild West has to have gunslingers, and since RWW is a setting hack for the Starfinder Roleplaying Game, that means I need gunslingers for that game… at least up to 10th level (RWW’s current cap).
That said, a big part of the fantasy gunslinger class is that it gives access to firearms, and makes them less-terrible and less-unreliable choices. Since small arms, longarms, and sniper rifles aren’t terrible choices and are easy to gain access and proficiency with, there’s no need for a class that takes up a lot of its abilities fixing those fantasy-rules-related issues. Also, RWW is the kind of setting where a mechanic, mystic, or even solarian could all be gunslingers, so why restrict the concept to just one class?
I’m working on a longer version of the Starfaring Gunslinger rules that will cover some archetypes and go to 20th, but that’s likely to actually be a full product. This is a preview.

There are two ways to get gunslinger abilities: the gunslinger archetype, and the gunslinger feat. You can use both, if you wish.

Gunslinger Archetype
You are more than proficient with guns, you are focused on them to a degree most gun users can neither duplicate nor understand.
Special: You must be proficient with small arms, longarms, or sniper rifles to take this archetype.
Gunslinger Ability: At 2nd, 4th, and 6th level you may choose to take gunslinger abilities as alternate class features (using the normal archetype rules).
If you make this choice more than once, each time after the first that you make it you gain two gunslinger abilities, rather than one. (Thus if you selected this option at all three level, you’d have five total gunslinger abilities.)

Gunslinger Feat
You are a master of slinging guns.
Prerequisites: Proficiency with small arms.
Benefit: Select one gunslinger ability.
Special: You can select this feat more than once. Each time, you select a new gunslinger ability of your character level or less.

Gunslinger Abilities
Regardless of how you gain your gunslinger abilities (feat or archetype), you can only select a gunslinger ability of your level of less. Unless it specifies otherwise, you can’t select a gunslinger ability more than once.

Gunslinger’s Dodge (Ex): [1st Level] You gain an uncanny knack for getting out of the way of ranged attacks. Once per day when a ranged attack is made against you, you can move 5 feet as a reaction; doing so grants you a +2 bonus to AC against the triggering attack. This movement is not a guarded step. Alternatively, you can drop prone to gain a +4 bonus to AC against the triggering attack.
Once you use this ability, you cannot use it again until you spend 1 Resolve Point to regain Stamina Points taking a 10-minute break, or regain your daily abilities. You can also use this even when it is expended by spending 1 Resolve Point.

Gunslinger Initiative (Ex): [3rd Level] As long as you have at least 1 Resolve Point, you gain the following benefits. First, you gains a +2 bonus on initiative checks. Furthermore, if you have the Quick Draw feat, your hands are free and unrestrained, and the small arm is not hidden, you can draw a single firearm as part of your initiative check.

Gunslinger Specialization (Ex): [3rd Level] When you take the attack of full attack action with a small arm, without using any class feature or feat that increases attack rolls or damage, you add damage equal to 1-1/2 your level to damage done with small arms (instead of Weapons Specialization’s normal bonus for small arms of half your level).

Pistol-Whip (Ex): [3rd Level] You can use your small arm, longarm, or sniper weapon as a melee weapon. Select a bludgeoning basic melee weapon with an item level lower than your ranged weapon. Treat your ranged weapon as this melee weapon for purposes of threatening spaces, making attacks of opportunity, and dealing damage, but grant it the knockdown critical hit effect (replacing any critical hit effect it normally has). When used in this way, the weapon still benefits from any weapon fusions it has that would apply to an unpowered bludgeoning melee weapon.

Utility Shot (Ex): [3rd Level] If you have at least 1 Resolve Point, you can perform all of the following utility shots. Each utility shot can be applied to any single attack with a ranged weapon, but you must declare the utility shot you are using before firing the shot.
Blast Lock: You make an attack roll against a lock within the first range increment of your ranged weapon. A Diminutive lock usually has AC 15, and larger locks have a lower AC. The lock gains a bonus to its AC equal to its item level. Hold portal grants a +5 bonus to the AC of a lock against this attack. On a hit, the lock is destroyed, and the object can be opened as if it were unlocked. On a miss, the lock is undamaged. It can still be unlocked by successfully performing this deed, by using the Computers or Engineer skills.
Scoot Unattended Object: You make an attack roll against a Tiny or smaller unattended object within the first range increment of your ranged weapon. For this purpose, a Tiny unattended object has an AC of 5, a Diminutive unattended object has an AC of 7, and a Fine unattended object has an AC of 11. On a hit, you do not damage the object with the shot, but can move it up to 15 feet farther away from the shot’s origin.
Stop Bleeding: You expend one usage of a ranged weapon and then press the hot barrel (or hot energy vent, or power cable, or some other part of the weapon that heats when it uses energy or fires) against yourself or an adjacent creature to staunch a bleeding wound. This ends a single bleed condition affecting the creature. You can do this in place of an attack (as a standard action, or part of a full action allowing multiple attacks).

Dead Shot (Ex): [7th Level] As a full action, you can expend 1 Resolve Point to make a single ranged attack, rolling your attack twice and using the better of the two results. This functions with Gunslinger Specialization and can be combined with the full action to aim and fire a sniper weapon, but does not work with any other class feature or feat that increases attack rolls or damage.

Startling Shot (Ex): [7th Level] If you have at least 1 Resolve Point left, when you successfully use covering fire or harrying fire against a creature, you also cause it to be flat-footed for 1 round.

Targeting (Ex): [7th Level] As a full action, you can make a single ranged weapon attack and choose part of the target’s body to aim at. If you hit, you inflict the following effects depending on the part of the body aimed at. If a creature does not have one of the listed body locations, the GM can determine if it has an equivalent body part or not [and may require a Perception or Life Sciences check (DC 15 +1-1/2 target’s CR) for you to know and recognize such an equivalent]. Creatures immune to critical hits or critical hit effects are immune to this ability.
Once you use this ability, you cannot use it again until you spend 1 Resolve Point to regain Stamina Points taking a 10-minute break, or regain your daily abilities. You can also use this even when it is expended by spending 1 Resolve Point.
Arms: On a hit, the target takes no damage from the hit but drops one held item of the your choice that it can drop, even if the item is wielded with two hands.
Head: On a hit, the target is damaged normally, and is also confused for 1 round. This is a mind-affecting effect.
Legs: On a hit, the target is damaged normally and knocked prone. Creatures that have four or more legs or that are immune to trip attacks are immune to this effect.
Torso: Targeting the torso causes any critical hit effect your weapon possesses to be triggered on an attack roll of 18 or better (the die shows an 18, 19, or 20) that hits the target’s AC, even though an 18 or 19 is not a critical hit.
Wings: On a hit, the target is damaged normally, and must make a Fly check (DC 15 + 1-1/2 your base attack bonus) or fall 20 ft.

This post brought to you by the City of Seven Seraphs, so check it out! They are a sponsor from my Patreon Campaign!

(My patrons also got their own exclusive preview of the larger work, with three abilities drawn from the blatherskite archetype of the gunslinger!)