Interesting story a Marine that had worked at US Embassy San Salvador related....
The Detachment was permitted off duty weapons after a Det had been gunned down in town during the 80s.
The Colonel came to inspect the Dets and as is customary there is a formal dinner.
When it came time for cocktails and the Det Marines removed their suit coats a variety of arms and double rigged shoulder holsters were exposed.
The Colonel supposedly flipped because the guys had bought some cool firearms locally, guns Tony Montana would have thought pimped up.
Anyway the Colonel asked rhetorically "He has a .45, you have a 9mm, what happens if you run out of ammo and than cant resupply one another?"
Of course someone didn't understand the idea of rhetorical and piped up to wit "Sir I am carrying (a large number) rounds right now and everyone has similar. If any of us run out of ammo it wont matter."
They were limited to State Dept issued S&W Model 19s soon after. 6 shots and two speed loaders probably for their load.