Nail'Em

Nail guns are a common Improvised Weapon in fiction. Generally, they are portrayed as being analogous to firearms that shoot nails instead of bullets. In reality, nail guns have to be in direct contact with something to fire. Even if they have been modified to fire without being in contact with a surface, their accuracy at range sucks. In other words, they make crappy projectile weapons. They make better melee weapons, since a nail gun is a blunt object that can stick out a long spike on contact, but this is hardly ever represented in fiction.

Nail'Em ignores Real Life in favor of the Rule of Cool.

The trope also covers the use of rivet and staple guns as weapons.

Examples of Nail'Em include:

Anime and Manga

Near the beginning of Highschool of the Dead, Kohta modifies a nail gun into an improvised rifle and consistently headshoots the infected with it.
Franky in One Piece can spit nails in a Gatling-like fashion from his mouth.

Comic Books

Blastosaurus: At one point, raptors shoot at the title character with nail guns.
Chucky kills the lecherous Sugar Daddy with a nail gun in Hack Slash vs. Chucky.

Fan Works

A nail gun is used for a particularly brutal murder in Ill Met By Moonlight.
Xander/Xendra uses a high-powered nailgun to slow down and incapacitate Adam in the Buffy the Vampire Slayer fanfic Xendra.

Film

In Small Soldiers, a nail gun is used as a heavy machine gun.
In Mousehunt, one of the two heroes is using a nail gun, not knowing that the mouse is behind the wall.
Lethal Weapon 2. Sergeant Murtaugh is attacked by South African agents and defends himself with a nail gun, ending it with him invoking the trope name.
Stay Alive: One character tries to use a nail gun to "nail" a vampire.
Event Horizon: Doctor Weir threatens other characters with a nail gun.
Arachnophobia: Ross kills a spider with a nail gun.
In Final Destination 3, one of the victims meets her end when shot by a malfunctioning nail gun.
In Cliffhanger, Gabe (Sylvester Stallone) uses a spike-gun to shoot a bad guy, but it's at close range, and it's pressed against a sheet of ice; so it might work.
In UHF, a mobster catches a few staples to the face.
James Bond (Daniel Craig) uses a nail gun for self defense against Gettler in Casino Royale.
The page image depicts a cover for the 1985 film The Nail Gun Massacre, a notoriously sub-par slasher which chronicles the killing spree of a maniac who, adorned in army fatigues and a motorcycle helmet, drives around in his gold hearse, killing semi-randomly with a nail gun while cracking bad jokes.
Hollis's death in the original My Bloody Valentine.
The most infamous scene in The Toolbox Murders features the killer chasing a naked woman (who was masturbating in the tub) around with a nail gun. In the remake, a woman is nailed to the ceiling with one, after being shot in the throat.
The Big Bad Strack uses a rivet gun in his battle with Darkman, high atop a skyscraper under construction.
In the Night of the Demons, Maddie loads a shotgun with extremely rusty wrought iron nails, one of the few things that can harm the demons. They lampshade in the commentary how utterly impossible this is.
In The Island, there is a particularly... disturbing example. Jordan and Lincoln are hiding in a bathroom waiting for one of the company's men to find them. The man finds them, and they lock the door. He punches through the brittle door and reaches over to unlock the door. Jordan nails his hand to the door.
A staple gun is one of the many makeshift instruments of torture utilized by the killer in Rest Stop.
A woman gets her vagina staple-gunned shut in one of the Violent Shit films.
The victims in The Human Centipede 2 (Full Sequence) are stapled together.
The main character's wife is shot in the head with a nail gun in Seed.
A rat and a pregnant woman are killed with a nail gun in The Carpenter, while a man is shot in the eyes with a staple gun.
A character is tortured with a nail gun in Bunnyman.

Literature

In Lois McMaster Bujold's Diplomatic Immunity, an automated hot riveter is used (after bypassing several safety interlocks) as an improvised automatic slugthrower.
In The Dresden Files novel Small Favor, Charity Carpenter uses a nail gun against the gruffs in the opening chapter, followed by beating their skulls with a heavy contractor's hammer. Since the gruffs are Fae, they are extremely vulnerable to the touch of iron, and retreat very swiftly.
Patrick Bateman from American Psycho uses a nail gun in quite a few of his murders, the most notable of which involves him nailing a woman's hands to a wall so many times her fingers start to fall off.

Live-Action TV

In CSI: Miami, Ryan Wolfe is shot through the eye by a nail gun, although here they do at least point out that the safety that prevents the gun from firing unless pressed against a surface is broken.
Reaper used nail guns in the first episode to capture the Baddie of the Week
Psych: In "Lights, Camera, Homicidio", the killer has been replacing prop weapons with real ones on the set of a Spanish soap opera. The last one is a nail gun, which the actress fires at Shawn before realizing it's really loaded.
The Wire features Snoop and Chris buying a nail gun in the fourth season premier, ostensibly for this purpose. It isn't used to commit the murders, but it is used to cover them up...
The Criminal Minds episode "Hopeless" has the killers nailgun a man's hands to a bartop before beating him to death.
Burt gets attacked with a staple gun he was returning in an episode of Raising Hope, after telling the person he was giving it back to that he's in the Sex Offender Registry.
Earl was shot on several different occasions with either a nail or a staple gun by Sweet Johnny.
The Smallville episode "Mortal" featured a pair of Creepy Twins who need to be touching each other to use their forcefield powers. Lana Lang manages to knock them apart, then nails one twin's hand to a wall. Disturbingly, the twin simply pulls his hand through the nail to free himself.
In an episode of Get A Life, Chris gets a job with the ancient brotherhood of contruction workers (just roll with it) and by the end has gotten into a tool duel with one of them. The opponent seems to have the upper hand when he brings out the ultimate tool duel weapon, a staple gun, but Chris is able to force him to surrender by utilizing a construction worker's greatest weakness and threatening to pour out the last beer.

Professional Wrestling

Staple guns were a staple (no pun intended) of ECW "garbage" matches.
- They were "used" correctly though, pressed against the target, as opposed to being used at range.
- They are still used today in "deathmatch" wrestling from time to time. This was shown in The Wrestler during Randy the Ram's hardcore match against the Necro Butcher. Necro, a Real Life deathmatch wrestler, is well known for doing stuff like this.

Tabletop Games

The smart nail gun from GURPS: Ultra-Tech is more accurate than most pistols and is surprisingly effective at piercing armor.
World of Darkness: Armory includes rules for using a nail gun as an improvised weapon. Notably, they have to be modified to use them at range, and in doing so, you lose any sort of accuracy.

Video Games

BioShock (series) uses a variation: The Big Daddies use a rivet gun as their primary ranged weapon. In the sequel, where you play as a Big Daddy, the first gun you pick up is a prototype version.
- One of the weapon options in the sequel's multiplayer is a nail gun.
Your main weapon in Dead Space Extraction is also a rivet gun.
Quake has Nine Inch Nail Guns. Contrary to most examples, they're some of the most accurate weapons in the game.
- Quake II Mission Pack 2: Ground Zero introduced the ETF Rifle - despite the name, it was basically just the nail gun from Quake I that ignored armor. It even sounded like the nail gun!
- Quake III Arena has shotgun nail guns. A nail gun that fires a shotgun-like burst of 9 inch barbed railroad spikes. Getting hit with this is almost always a One-Hit Kill and causes you to get thrown backwards a huge distance, sometimes leading to a fall to your death.
- Quake IV, true to tradition, has a usable model as well. However, besides being rather consistent in its accuracy from the start, it can be modded so that the nails can chase the target. Even around corners.
Home Improvement
Hitman: Blood Money allows you to use a nail gun, but you'll find it to be slow to fire, so short in range that you literally have to be in the face of the guy you intend to kill with it and the accuracy blows.
Team Fortress Classic: The Scout has a nail gun.
- The Medic's Super Nailgun is better.
- The Nail gun was for a long time going to be the Scout's primary weapons in Team Fortress 2 as well (it was even featured in one of the trailers), but was replaced with the Scattergun; this is referenced in how Dispensers seems to have a nail belt hanging out of them. It's been made into a custom skin for the pistol, but it only affects how it looks.
- The Medic's Syringe Gun is essentially a cross between this and an SMG.
The F.E.A.R. games have the Penetrator series of rifles, which fire high-speed ten-millimeter spikes designed to penetrate armor. As an added bonus, when close to a wall or other large object, the Penetrator could stake enemies to said objects.
Manhunt: The Skinz gang is armed with nail guns.
The secretary unit in the Flash game HRmageddon uses a staple as a ranged attack weapon.
The MMORPG Neocron had nail guns as newbie weapons.
Harry The Handsome Executive uses a staple gun.
Fallout 3 has a slight variation in the Railway Rifle, that doesn't shoot nails as much as railroad spikes.
- The Fallout: New Vegas DLC Lonesome Road adds H&H Nailguns, which work like silenced sub-machine guns.
Geist allows the player to possess a worker who has a rivet gun. While it's useful in a literally riveting action sequence, it's not much of a ranged weapon.
One of the many enemies in Ratchet and Clank Going Commando is a berserk construction worker bot with a rivet gun. It has horrible accuracy and range.

Web Original

Shakila from ~Darwin's Soldiers~ lures a Mook into an empty building that is under construction and kills him by placing the nail gun against his neck and shooting some nails into him.

Western Animation

In the episode "False Start" of Code Lyoko, XANA materializes some Kankrelats to the real world. One of the weapons the team uses is a modified nail gun, and it gives a crowning moment to Jim.
In The Venture Bros., Brock Sampson uses a nail gun to save Dr. Venture from falling. The nail gun is shown firing with precise accuracy, though the third time he accidentally pinned Venture through his body instead of by his shirt. Brock also uses it to dissuade an approaching enemy who's actually bigger than he is.
The Simpsons: In one episode where Homer goes berserk over baby-proofing the house for Maggie, he hands Maggie the Nail gun. She nails his hand to the wall from ten feet away. Homer realizes how in trouble he is, and attempts to coax Maggie into giving back the gun. She pins him to the wall with at least four more nails, with one landing in each ear.
- In another episode, Homer and a new friend have a light-hearted sparring match with nail guns. They each get several shots point blank in the face which do no more damage than snowflakes.
An episode of King of the Hill had Cotton snap and hole up in a newly-built house with a nail gun.
In Family Guy, when a boy was faced with taking Meg on a date, he resorted to shooting himself in the stomach with a shop class nail gun to get out of it.

Real Life

A man in Australia was murdered by being shot 34 times in the head with a nail gun.
Nail gun injuries crop up frequently in the Darwin Awards (including one attempted suicide).
Bolt pistols, used in slaughterhouses to stun livestock and for in-the-field euthanasia of injured farm animals, operate on a similar principle to nail guns.