It appears the internet has come through once again to expose potential flaws in our beautiful society. The web increases everyone's visibility, so it can be a good barometer for how people would interact if it were in-person.
In this case, the direct sale of a weapon.
This is perfectly legal in the United States, as any person can sell any person a gun so long as the person buying (or selling) isn't a convicted felon. It's up to the felon to be honest though, because, despite polls favoring background checks at 92 percent of the country, there isn't a law requiring the seller to find out.
Gun salesmen are now finding Instagram particularly useful as a marketplace, because what AK-47 doesn't look get in sepia tone? Sellers flash their stash and interested buyers leave comment, then switch over to private messages.
That's how easy it is to acquire a weapon without a background check in this country, and looks a lot like what people wanted to prevent in the wake of Sandy Hook.
This is something lawmakers will have to somehow address, but, as usual, the path leading there is arduous. Gun activists will obviously fight to keep the laws as they are, as they always do. Internet activists will condemn government overreach of internet marketplaces. Ultimately, this may come down to companies that don't want this going on blocking users and creating guidelines against it, in the hopes that it forces the marketplace on to something that can enforce background checks. But then again, that doesn't work either due to privacy activists.
Ah, who am I kidding? The government doesn't listen to privacy activists anyway.