To be fair, guns aren't exactly unknown in NI, either!

There are 153k people who have legal firearms (so about 10% of the adult population, vs about three times that in the US). That's largely farmers with shotgun licenses (NI is pretty rural by European standards) plus licensed "weapons for personal protection" for people exposed to threats for whatever reason as a legacy of the Troubles.

And then there are some unknown number with illegally-held guns - the main armed groups put their weapons "beyond use" as part of the decommissioning process in the 2000s, but inevitably some will have been missed, and then there are the dissident groups who still hold significant amounts of weaponry.

Hard to put an exact figure on it, but if you guesstimate it at a weapons ownership rate at about half that of the US you probably wouldn't be too far from the truth.

So even after accounting for the differential in gun ownership, SFPD are still shooting people at ~25x the rate of the PSNI.