This ring of true Grit allows a gunslinger to use their mighty endurance and using a grit point you can have one of the following effects happen

By spending one grit, you may nullify a misfire that happens with your gun.

By spending two grits you may instantly reload your gun without having to spend an action, in addition you recover one extra thing of ammunition

and by spending three grit points you can lower the DC for a natural crit by 1d4 x the amount of remaining grit you have left. If you have no grit remaining then it is just 1d4