These weapons are not available for use in the game, but are often depicted in several ways, often in in-game media. Unlike in-game weapons, they are exact representations of their real-life counterparts.
Some artworks depicts a what appears to be a M4 carbine variant with a CQBR (short barrel) configuration (also known as the "Mk 18 Mod 0"). The ones carried by Trevor has a scope attachment, while the ones carried by Michael has a scope and a suppressor.
One of Trevor's artworks depicts him on a Blazer quadbike and holding and unknown Sniper Rifle. [citation/verification needed]
There are some depictions of Glock-styled pistols, such the one seen in some artworks of Franklin.
In one artwork of Franklin and Michael preparing for The Jewel Store Job, a piece of paper with the option "Guns Blazing" (Loud and Dumb) depicts an MP5-style SMG and an AK-47-style assault rifle.
Artwork of the Bullpup Rifle released during the run-up to the High Life Update suggests that it was originally going to be modeled after the L85A2, featuring the same receiver, handguard, charging handle and carrying handle.
Various NPCs such as Gruppe Sechs guards, LSPD officers or Merryweather operatives are seen with differently-modelled pistols on their holsters. Though hard to see, it is assumed to be a Glock pistol, with the large rear sights similar to that of a Glock 23.
In the TV show The Underbelly Of Paradise, several weapons are depicted in the illegal weapon trafficking. The handguns depicted in the same screen appears to be a SIG Sauer P226 (with no clear sights of a hammer) and an unknown Glock pistol.
Handguns in GTA V are the only weapon class in which reloading differs when the magazine is empty or not.
In GTA Online, weapon attachments unlock as you increase your rank. For example, you unlock the Advanced Rifle at Level 70 and the Extended Clip for the Advanced Rifle at Level 71.
DLC weapons are located next to the original ones, listed in the appearances order (i.e., the Gusenberg Sweeper will be before the Bullpup Rifle). However, the Sawed-off Shotgun can be placed here first if the Assault SMG is available.
Sometimes, guns dropped on the ground by NPCs will randomly discharge, as seen here.
As demonstrated on the gameplay video, weapon system on the enhanced edition of GTA V now introduces the ability to throw grenades while holding a weapon. It is done by either pressing Left on the D-pad, or by swiping the Dualshock 4 touchpad upwards. On the PC version, it can be done by pressing "G" whilst aiming. It is available in both first and third person modes.
Most of the game's weapons feature reload animations unrealistic towards real firearms (for example, shotguns are always pumped after reloading, even when not empty, which while possible would needlessly eject a loaded shell.) However, this was likely done to allow for speedier reloading in game.