But I don't think high-damage guns and reduced hp PCs is part of the solution, either. HP are a central mechanic in D&D, they're essentially plot armor, and old-west heroes are as plot-armored as any others. Their hats get shot off, their friends get shot, their horses get shot out from under them, posts & waterbarrels & windowsills get shot right in front of their faces, and they take shoulder wounds with alarming regularity, but they don't get killed so much relative to the amount of lead flying around.
Now you come across as someone unfamiliar with other role-playing designs than hit points and levels, but I'm sure that's not really the case.
Meaning all of that is certainly not a defining feature of hit points, and in fact, a way to use hit points that is deeply unsatisfactory to many.
How's that? Because with hit points you *know* the first stab or bullet is not going to reduce your fighting capability in any way. Not everybody is capable of feeling the excitement and (exaggerated) fear of death there.
This is a major reason why other RPGs were invented.
That is, to better model a scenario where each bullet could kill you (but not really, since you're a hero). But fundamentally, to replace hit points with Dodge tests, built in physical resistance, and relying much more on armor, cover and tactics.
If all you know is D&D, it is very hard to see and appreciate this. Not that this applies to you. Right?
For a general set of expectations on gun duels, I am arguing one of these games, where hit points don't increase with levels, is a better fit.
(And for the umpteenth time, not because D&D is bad, only because it's suited to another set of expectations on how a combat "should" go down)