Backwards-Firing Gun

They say that in the army

The guns are mighty fine

But when you pull the trigger

The bullets fly behind!

This is a comedy weapon trope (although there are dramatic examples) featuring a gun designed or modified to fire backwards, tricking the person who uses it into shooting themselves. A common version seen in cartoons is to bend the barrel back into a "U" shape. Note that this trope may still come into play even if the person who might fire the gun would have to be really stupid not to notice the modification.

These guns tend to show up in cartoons and spy genre pastiches.

Despite the trope title, other projectile weapons, such as a crossbow or ~~hwacha~~ Hwacha!!!, may be examples of this trope.

Compare Had the Silly Thing In Reverse.

Examples:

Anime and Manga

Umineko no Naku Koro Ni: Battler suggests this to explain one crime.

Comic Books

A Franco-Belgian comic book involving a zombie problem features semi-automatic pistols tricked out to fire their sliding barrel backwards, killing the user.
Spy vs. Spy: As seen in the page image, this occurs in one strip drawn for a series of paperbacks.
An issue of the Impulse comic book guest-starring the Riddler featured said Crown Prince of Conundrums with a revolver rigged to shoot backward.
Used seriously in one Torpedo story, where the killer commissions a special one-shot gun for this purpose, replacing a cop's gun with it.

Film

Happens with a wrongly assembled cannon in Buster Keaton's The Playhouse.
In the 1966 film The Silencers (part of the Matt Helm series starring Dean Martin, a parody of the spy genre), a guard got hold of one of these guns, not knowing it was a trick gun, and pointed it at a woman - as she stoically awaited her fate (she didn't know what it was either). The guard pulled the trigger, shot himself, looked kind of puzzled, and shot himself again.
In Casino Royale 1967, George Raft, who was best known for playing gangsters, is shot with such a gun.
In Ballistic Ecks vs. Sever the big bad tricks a lackey into killing himself by giving him a backwards firing pistol. More of a loyalty test with a built in punishment, since he was told to shoot himself with it.
In the 1989 Tamil film Apoorva Sagodharargal, the dwarf Appu tricks Sathyamoorthy into killing himself with a circus hand gun that shoots backwards.
One of these shows up in The American when George Cloony's character intentionally designs one for an assassin. Why would he do this? Simple: He figured out that the assassin would use the gun to kill him.
An alternate ending for Die Hard With a Vengeance has John McClane threatening Simon Gruber with a Chinese rocket launcher with the sights removed, allowing Gruber to point the rocket whichever way he liked. Gruber ultimately points the rocket launcher the wrong way.

Literature

The Lovejoy novel The Judas Pair featured a pair of duelling pistols designed to fire backwards. The owner would challenge someone to a duel and let them fire first. His opponent would end up shooting himself in the face. This story was also made into an episode of the Lovejoy TV series.

Live Action TV

In "The Girl Who Was Death", a zany spy-spoof episode of The Prisoner (original), Number 6 modifies some rifles so they'll fire backwards before some guards arrive and attempt to shoot him with them. He also modifies German "potato-masher" grenades so the charges are in the handles instead of the heads.
In an episode of The Wild Wild West, Miguelito Loveless hands James West such a pistol, but he sees through the ruse.
- Said gun pulls a Chekhov at the end of the episode, when Loveless pulls a gun on a hostage, only for West to remind him that there were two identical-looking guns in the bag, only one of which shot forwards.
Happened in a Benny Hill skit that spoofed The A-Team.

Newspaper Comics

FoxTrot did this with a squirt gun in one strip.
Urbanus: In "De dochter van Urbanus", there are three of them.

Radio

In the BBC radio drama Batman: The Lazarus Syndrome, Ra's al Ghul accidentally shoots himself when he grabs a gun from Batman's trophy room, not realising that it is a booby-trapped weapon rigged to fire backwards.

Tabletop Games

Grimtooth's Traps Too contains a reverse-firing "Double Crossbow" as a loot trap.

Video Games

Cobra Triangle: One of the two forms of the top of the Fire power-up chain fires one bullet from the fore, one from the aft, and one each starboard and port.

Western Animation

Occurs in numerous Looney Tunes shorts.
- Apparently you can make any gun fire backwards if you stick your finger in the barrel.
- In one notable example, Bugs Bunny removes the sight from Wile E. Coyote's rifle so he can't tell which end of the barrel is which.
- And in Hillbilly Hare he does it by turning the barrel of a long rifle round after the trigger has been pulled.
- A Farscape episode in which Crichton imagines himself in a Looney Tunes cartoon has him pulling this trick by sliding the sight forwards on D'Argo's shotgun. An angry D'Argo swops the barrel round, only to shoot himself a second time.

Real Life

A poorly-made, incorrectly assembled or worn-out firearm or excessively powerful cartridge loads can cause the bolt, part of the breach or -in the case of semi-automatic pistols- the slide to be blown back into the user's face. The Shur Fine Guns page has a couple of examples.
Water guns have been made so that there's a rotating exit on the top allowing guns to squirt in any direction and forward at the same time.