Beta Weapons are a series of minor Easter eggs throughout the Grand Theft Auto series.
Beta Weapons refer to any weapon originally intended to be in a game that exist in some form within the game's files but are not included as usable weapons in the final release. The Grand Theft Auto series is littered with subtle implementations of these discarded weapons in both cut-scenes and live play.
GTA Vice City
The MP5k is a variant of the MP5, which is already included in the final version of the game. It is used by an assassin during the introduction cutscene of the game, In The Beginning.... It is possible to replace the vanilla gun with the MP5k via mods.
The nailgun was cut from the final game. It can be seen in-game on tool shops, but it's not usable. It still exsist in the game files, but only on PS2 it has a proper icon.
The Steyr-AUG can be seen on some pre-relase screenshots. The weapon exsits in PS2 Game files, but it was removed from the game. It was most likely replaced by the Python.
GTA III Leftover Weapons
Some weapons from GTA 3 are left in PS2 game files. They can also be seen on some screenshots, like the Shotgun. The only one that is left on PC version is the AK-47. It can be swapped, but the model will not stay correctly in Tommy's hands.
The stun gun model exsists in PS2 game files. Nothing more is known about it.
The ingram was supposed to have a silencer. It was cut and the silencer was removed. However, this idea was re-used in Vice City Stories.
The Grenade Launcher was removed from Vice City. It was most likely replaced by RPG.
The desert eagle was cut from the game and was probably replaced by the Python. It can be seen on some cutscenes like Rub Outand The Shootist. The Desert Eagle was reused in San Andreas and the trigger was fixed.
GTA San Andreas
During the mission Stowaway, FBI agents crewing the Andromada aircraft can be seen wielding an M16A1 assault rifle that exhibits a unique camouflaged texture. The weapon is not available to the player and the FBI agents will drop a regular M4 upon death. This M16 shares the texture with the one from another Rockstar game, Manhunt.
The Colt Python appears as an unusable model in Ammu-Nations across the state. The revolver is a usable weapon in San Andreas' predecessor, Vice City, and was just a simple texture import.
The colloquially named Colt pistol of San Andreas is based on the Colt M1911A1. However, there are many discrepancies between the statistics of the real life Colt and the in-game one. The Colt is referred to as a 9-millimeter and has a 17 round magazine, but in real life, the Colt fires .45 caliber rounds and usually holds 7 rounds per magazine. This is because the Colt was originally going to be a Glock 17 pistol, but was changed.
While not usable by the player, the Glock can still be seen in cut-scenes, most notably wielded by Jimmy Hernandez and Eddie Pulaski in the opening scene of the game, Ryder in the first cutscene of the mission Ryder and later by Mike Toreno in his own titled mission, Mike Toreno.
The Israeli Military Industries UZI was once intended to be the signature weapon of the Grove Street Families, lasting until the game's beta version, but was replaced with the MAC-10 and reassigned to the Ballas gang with the TEC-9 taking its place in the Grove Street arsenal. The Uzi model can still be found in the game, as a statue of Big Smoke is holding the weapon, along with a shotgun, on the top floor of Big Smoke's Crack Palace. UZI was also originally present as a usable weapon in GTA Vice City.
The MP5-K appears in the game's files using the same camouflaged texture present on the M16A1 during the mission Stowaway, during which, a box labeled "MP5-Ks" can be found. The models themselves are ripped directly from GTA Vice City. Also, these boxes also appear in the previous mission, Catalyst. The model still exsists in gta_int.img called "cj_mp5k.dff."
The PSG-1 sniper rifle is present in the game's files and also shares the same camouflaged texture present on the M16A1 during the mission Stowaway.
The skateboard was going to be used in game as a source of transportation and a melee weapon. It is likely that the ability to access it was cut late in development, as there are strings of code refering to it, an icon, model, and a pick-up point in one of the unused burglary houses. It would have been introduced to the player in the mission Madd Dogg's Rhymes.
During the mission High Noon, a unique shovel can be seen used by the C.R.A.S.H officers. Unlike the usable, in-game shovel, this one exhibits a square head. It once again borrows its texture from GTA Vice City.
The Franchi SPAS-12 was intended to be a useable weapon within the game and remnants of it can still be found within the game's files, but it was later replaced with the Combat Shotgun. The SPAS-12 is featured in two artworks, one of which shows 2 LSPD officers wielding the weapon, and another with the protagonist, Niko Bellic, holding the weapon. There were originally intended to be two variants of the gun, one with the stock folded out, used by police, and another with the stock folded up, for use by criminals. It is unknown why the SPAS-12 was removed so late into the game's development.
While the Glock that is usable in the game is based on a Glock 22, the third generation Glock 23 can be seen in the holsters of police officers. However, they will use the standard Glock 22 in combat.
The Heckler and Koch MP5A3 is the old version of the game's SMG. It was shown in an early screenshot before the game's release, displaying Niko crouching behind some crates with the weapon readied. Players have noted the unusual half-size 15 round magazine of the old MP5A3, but this could be due to the angle of the screenshot.
The IMI Uzi made its debut in The Ballad of Gay Tony, but was first planned to be included in the first expansion, The Lost and Damned. It shows up in various artworks for the game, usually being held by in game character Angus. However, unlike The Ballad of Gay Tony's Uzi, this one is not solid gold.
Sawed-off Remington 870
A sawed-off Remington 870 was going to appear in a prominent role in the game, but its only presence in the released version is a loading screen artwork and easy-to-miss appearances in a few cut-scenes, wherein the gun is not fired. It is believed the 870 model was re-purposed for GTA V. Some parts of the model were later used for the double-barrel shotgun in The Lost and Damned expansion.
The SW MP-10 was an early contender for the Assualt Carbine's spot and can still be found in the game's files. The old model also featured in one of the trailers. It has an identical model to the finished version, but has a blurry and unfinished texture.
Due to Niko's Serbian origin and the heavily Slavic influenced theme of the game, the AK-47 based Assault Rifle was originally going to be a replica of a Serbian manufactured Zastava M70AB2. The weapon was similar to the Assualt Rifle’s final model, but had different iron-sights and a folding stock. It can still be seen in the That Special Someone trailer for the game. It is also featured in an artwork for in-game character Little Jacob.
In the trailer for the game, Trevor can be seen holding an assault rifle with what players originally thought to be a laser attachment. However, if inspected closely, the Laser appears quite low under the weapon and is also visible through the clearing between Trevor's Shoulder and the rifle's grip, indicating the laser actually originated from a Sniper aboard the Police helicopter.
An artwork for the High Life Update suggests that the Bullpup Rifle was originally modeled after the British L85A2 assault rifle. However, in the final version, it is clearly based on the Chinese QBZ-95.
SR-25/Mk 12 Replica
A sniper rifle resembling an SR-25/Mk 12 can be seen wielded by both Michael and Trevor during some artworks and, in the newer update files, the cut SR-25/MK-12 Hybrid HUD and texture files can be found. It was to be named Assault Sniper in-game.
The pipe wrench has been added as a melee weapon in GTA Online as of the Bikers Update. It can still be seen and used as a torture device in the mission By the Book.
.357 Colt Python
One of the original concept art designs for Ron shows him holding a .357 Magnum revolver. Whether it was actually going to be added to the game or not is unknown, though future updates did allow the player access to other revolvers such as the Heavy revolver and the Double-Action Revolver.