I’m usually against drabble; I’m not against this. Go read it now.
 short version: the constraint is uninterestingly arbitrary, and very few authors are up to the limitation; much as “five-minute horror film” almost always translates to “one dumb jump scare,” “drabble” almost always translates to “squandered half-an-idea.”
… but just a reminder to my American readers: We already live in this reality. This country isn’t just full of guns; it’s full of ammunition. If you have access to even a single bullet, you are $10 and a trip to the hardware store from making a wonderfully lethal weapon: unserialized, untraceable, highly concealable, nearly foolproof. You won’t be doing any civil massacres with a hardware-store slam gun, but you can mostly definitely kill the guy standing in front of you with little effort.
The reason no one will shoot you today is because no one feels like shooting you today.
… My time portal novel is now on Amazon (print and ebook). It’s a giddy little thrill at a reasonable price.
I’ve read a million time travel stories… and even read a million variations on time travel stories that try to be “different,” but I don’t think I’ve ever read any that are different in quite this way. While it settles uncomfortably next to very serious and even tragic things, the story’s humor is quite pronounced. … And it does an excellent job of creating an air of danger, and thus interest, due to the well-realized sense of actual traveling in (and perhaps getting lost in) time, as well as the criminal aspect and what they’re doing to the people in the past and how those people might react. It’s also a good vehicle to address issues all the way from existential bad faith to religion possibly being the amphetamine of the masses.