Puerto Rico (I've lived here since 2018...) is basically awash in guns for criminals. Since 2020, it's gotten a lot easier to buy/carry guns as a normal person (previously you had to appear before a judge for a ccw, now it's a 1h class and $100 for 5 years). It's the only non-warzone I've lived in where the default criminal gun is fully automatic (usually glocks with switches, but a few other things too). Absolute guns per capita isn't really what matters, it's gun accessibility to criminals.

(And the bigger crime issues in PR are due to dysfunctional/bankrupt government, specific kinds of poverty/culture, drugs (both local and transshipment), gangs, etc. Also really high domestic violence rate. The crime is largely contained to housing projects, inter-gang fighting, etc., and it feels like less petty property crime (at least in the areas where I go) than I remember of SF 2016+, but I'd rather have someone break my car's window than have to shoot people breaking into my home at night.)