- Most PAYDAY 2 weapons were modeled after airsoft products, and thus have some minor differences from the real iterations of said firearms.
- For what is presumably ease of development, every weapon in the game seems to use a single set of three generic types of ammo, as they all replenishes spent ammunition from the same kind of drop which, upon closer inspection of the boxes' model, are 5.56x45mm NATO rounds, .22LR pistol bullets and 12-gauge shells.
- That being said, they do not share the same "generic" ammo pool.
- The ammo holders for each weapon are now correctly and consistently referred to as "magazines" instead of "clips" like in PAYDAY: The Heist.
- In The Guide of Bain, there is even a section ("Weapons") where several instances of "clips" were crossed out and "magazines" were written nearby in red marker as corrections. This is a reference to the constant nagging the developer team received from fans for repeatedly confusing between the two terms in the first game.
- There are several technical errors present in the many weapons available in the game. This is probably because of lack of thorough knowledge on real-life firearms on the developers' part, or for gameplay purposes. Weapon-specific goofs can be found on their respective pages.
- Man-portable light machineguns are specifically designed with recoil dampening and ergonomics in mind, and thus are capable of being shoulder-fired with enough training, which some heisters do have according to their background.
- Shotguns bizarrely have the ability to launch corpses a significant distance away. According to Newton's third law, every action has an equal reaction going in the opposite direction. Should the same happen in reality, the heister wielding the shotgun would also be thrown backwards after firing.
- Grenades launched from launchers do not have a minimum arming range.
- Bullpup weapons like the UAR and Lion's Roar all have horrible Stability. In reality, most bullpup rifles are designed to be rear-heavy with large, shock-absorbent stockpads to increase the contact surface area with the user's body, increasing grip strength and negating most of the generated recoil.
- Despite most weapons being capable of performing a tactical reload, none of them seems to be able to retain the round currently in battery. Put simply, the "one in the chamber" rule does not apply.
- Most of the weapons featured in-game are distinctively loud prior to being suppressed. This combined with the fact that a fair number of heists in the game takes place indoors or otherwise features close quarters means that permanent hearing loss would be a concern were any bit of realism to be portrayed verbatim in the game. A four-man crew opening up with their automatic weapons inside a tight-quarter meat truck in Watchdogs would soon result in a four-deaf-man crew in reality.
- Automatic weapons in the game all have a rather strange and exaggerated recoil behavior, with the entire weapon simply being jerked all over the place during a protracted burst rather than travelling rearwards like they would realistically do. While recoil does cause the muzzle to tilt upwards after each shot, it is influenced more by the shooter's physical strength than actual kickback.
- For the sake of balancing, all weapons and mods have to be nerfed down in certain aspects (accuracy, stability, damage, etc...) and assigned certain (sometimes exaggerated or downright incorrect) performance deficiencies so they won't overpower each other, often resulting in assault rifles with particularly wonky handling (AMCAR) or submachineguns taking more than one solid headshot to kill (e.g the Compact-5 on anything tougher than a security guard).
- In reality this will fail quality inspection for a majority of them as all firearms were designed and tooled with performance and efficiency in mind, "balancing" in any shape or form is largely non-existent and non-applicable; that's saying nothing about the fact that gun companies often had to compete with each other, and producing weapons with inherent faults might not be a very wise thing to do.
- On the flip side, other features of some weapons and mods are ridiculously exaggerated, such as the absurd stopping power on the Patchett L2A1 or the three non-melee weapons included in The Butcher's Western Pack, or the CAR-4's extreme versatility despite most of its mods only serves to improve its visual (or tactical capability, as in the case of its many Foregrip mods) in reality.
- Convection is never taken into account in normal gameplay. A firing Flamethrower Mk.1 or the fire patch created by a Molotov Cocktail would generate intense amounts of heat while active, and will potentially steam everyone to death if situated in a confined space.
- Certain weapon mods are also presented in rather bizarre ways not commonly seen in real life, or are not usually used as depicted in the game for reasons of efficiency.
- Long Barrel mods on most weapons actually reduces damage instead of increasing it. Conversely, several Short Barrels also increases this stat, despite the shorter barrel length not providing the spin time for a projectile to achieve terminal velocity.
- It is unclear in what manner are Barrel Extensions attached to the muzzle of most shotguns in the game as none of the available weapons of that type have barrel threads, be they external or internal. Several other specific weapons also cannot be silenced in real-life, like the Deagle, yet they can be fitted with a suppressor in-game.
- All extended magazine mods for pistols are modeled to protrude a significant length from the weapon grip's base. It is unclear why would the developers do this, as common expanded magazines of this, or any type for that matter, are simply resized versions to accommodate additional stacks of ammo, and while some are substantially widened, most are not necessarily longer in length. Even those that do tend not to extend very far from the weapon.
- The Alpha Mauler and Pen are currently the only Event melee weapons in the game.