Yeah it was bench seating so one guy had the reins and the other had a shotgun. Hence the name.

The apocryphal story is actually kind of interesting.

Roads and right of way established during the pre-firearm era were that you'd ride on the left, with people going the opposite way on your right. This was so you could use your dominant hand (usually your right) to use a sword to defend yourself.

Roads after firearms were available often established right of way with riding on the right, with oncoming traffic on the left. This is because when you shoulder a firearm on your right shoulder it's easier to aim left.

Stagecoach drivers would sit in the left seat, with the extra person sitting on the right, holding a shotgun, hence the colloquial term for the front passenger seat.

I have no idea how true this is, but it makes for an interesting story.

I'm the times coaches like that became common it wasn't really safe to travel in most parts of the world.

No, but many needed to protect those passengers from bandits and other assorted outlaws.

While this is probably some bullshit from the horse drawn carriage era, what I'd like to say is that statistically speaking riding shotgun is the most dangerous seat in car crashes, so the saying still works

It means "quick marriage because the bride is pregnant" and that is 100% the origin of the phrase.

Particularly in poorer, rural parts of the USA having a child out of wedlock was incredibly shameful, and the financial burden of a single motherhood was intolerable. So the bride's family would ensure the man responsible married their daughter ... regardless of how he felt about it. Sometimes that meant having a shotgun at the wedding to ensure he didn't run off.

I'll try and explain, but let me know if you don't follow. In the US it's common to claim the front passenger seat by saying "I call shotgun!" or simply "Shotgun!" The commenter is playing on a now common refrain where Americans use firearms and terminology to describe basic things. As far as I can tell, it's true. For example: caulk gun, staple gun, nail gun, glue gun, tattoo gun, finger guns, ot phrases like "I'll think about it before I pull the trigger on it." Or "Shoot me your email and I'll get you those photos."

I don't know how prolific this type of thing is in other countries though, so I can only assume we Americans arr outliers due to how deeply ingrained guns are in our culture. Hope this clarifies things a bit, let me know if not.

TLDR: Americans describing so many things: "So imagine a gun, but..."

They're saying, no, it's not common for other cultures to call it a gun thing. But in a humorous way, by drawing attention to the absurdity of the question.

wait, it's illegal to drink anything while driving in places? when did that happen?