Although also useful for documenting cute dogs and morning runs, gun dealers have found a legal loophole that allows them to use Instagram to hock illegal weapons through the photo sharing app.

According to a recent report from the Daily Beast, a simple search can turn up plenty of available firepower from handguns and shotguns to assault weapons and sniper rifles. Because there is no federal law banning online sales of firearms between two individuals and local laws vary from state to state, the market is basically unregulated. (It is illegal under federal law to sell to someone prohibited from owning a weapon, but background checks are not mandatory in person-to-person transactions in every state.)

Instagram's guidelines don't explicitly cover firearms either, probably because it was never meant to be used as an online marketplace. The guidelines do prohibit the sharing of illegal content and anything that will "promote or glorify self-harm." Craigslist, by comparison, has long since distanced itself from gun sales, explicitly banning them from their online classifieds.

The Daily Beast details how these online gun deals go down, and they're much less shady than your typical black market dealings:

A typical gun-toting Instagram post goes something like this: “‘LWRC 10’ SBR FOR SALE!!! Come get it! Includes AAC suppressor tip, ergo grip, 3 magpul pmags, 2 40 round mags, bungee sling, and about 500 rounds of .556. Message me if interested."

The negotiation then unfolds in the comments.

"Great setup," a user says, indicating his or her interest. "Asking $3000 for everything," the seller replies. "I'm really trying to get a package deal. Don't need want to part it all out."

After that, the deals move to email or phone calls.

Earlier this year, the Fix Gun Checks Act of 2013 would have closed the loophole that makes these types of sales legal, but it was shot down by the Senate in April, which President Obama called "a shameful day for Washington."

[Daily Beast] h/t [Gawker]