All efforts are credit to jackjack86 modder, his mod link is here : https://outward.thunderstore.io/package/jackjack86/Outward_Revolvers_Plus/

His mod has some problems about cannot loading pistols, un-unified recipes, not working recipes, and so on.
I corrected his works. At now, everything works perfectly.

FEATURES :

All Revolvers durability is buffed(+150~175).
Revolver shoot 6 bullets so need more lifespan, imo.

All Revolvers recipe is unified except for Revolver, Hailfrost Revolver, Chalcedony Revolver.
Revolver recipe : Flintlock Pistol + Palladium Scrap
Hailfrost Revolver recipe : Hailfrost Pistol + Cold Stone + Revolver
Chalcedony Revolver recipe : Chalcedony Pistol + Palladium Scrap + Revolver
Except for 3 pistols above, All Revolvers recipe : Original Pistol + Revolver
(For instance, Obsidian Revolver recipe : Obsidian Pistol + Revolver)

Meteoric Revolver is added.
Meteoric Pistol is legacy item from Obsidian Pistol. (DLC Required)

Bone Revolver is buffed for ethereal damage.
Physical Damage : 32 -> 25
Ethereal Damage : 32 -> 45
Cause merc character is hard to take down undead type monsters.

I use Thunderthore Mod Manager, so unzip file, copy & paste folder to
AppData\Roaming\r2modmanPlus-local\OutwardDe\profiles\YourProfileName\BepInEx\plugins