The Cavity 9mm is a compact, high damage semi-automatic rifle. In combat, its raw strength allows the player to kill many enemies with one solid body shot, and Maximum Force Responders with one headshot. It is also reasonably accurate, which helps with nailing down precise shots at long range.
The most obvious downside to using the Cavity is its semi-automatic firing mode. This cannot be changed, even by way of mods, making it ineffective in tight quarters. Its high base recoil also restricts it to firing from long range as well.
Specific builds for the Cavity 9mm are heavily skill dependent, as the performance is so strongly affected by the skills mentioned above. In particular the Fugitive skills are sensitive to concealment and therefore the optimum Cavity build may depend on the player's preferred secondary weapon.
Note that in general, the Tooth Fairy Suppressor (-1 dmg, +4 acc, -8 stb, -2 con) underperforms compared to a combination of The Bigger The Better Suppressor and the Appalachian Foregrip (in total: -1 dmg, +8 acc, -12 stb) as extra accuracy is available via skills such as Steady Grip.
Although the main flashlight has a toggle switch, the laser sight component of the LED Combo is pressure-activated, meaning the laser will stay on as long as the pressure switch is depressed. This switch is not placed where it should be, however (on foregrips, magazine wells, etc...) and is instead ziptied to the main taclight, leaving no plausible mean for the user to toggle it without awkwardly moving their off hand off the weapon and gripping the attachment itself.
Requires a pre-installed sight mod to mount. The magnification level can be changed while aiming down the sights, and the aiming FOV will automatically adjust itself. Not compatible with the Acough Optic, Military Red Dot, Milspec Scope, Combat Sight, Reconnaissance Sight, Theia Magnified Scope, Box Buddy Sight, the JP36's Original Sight, the Raven's Flip-up Sight or the GROM and Platypus 70's iron sights. Currently bugged and not appearing as intended on certain weapons, for a list see here. They're still listed below even if broken.
Upon release, the default reticle of this sight was a chevron instead of the retail version's red dot. After the release of the Gage Mod Courier DLC, it was reverted to the regular sight's red dot.
It is functionally the same as the standard Military Red Dot Sight, but the sight's casing is tan instead of black with the line "A-10" scrawled on near the adjustment knob. The sticker on the lens cap's interior also says "I <3 Payday" instead of having a picture of an American flag.
This sight was based on the Aimpoint CompM2 optic. While it is portrayed as a high-zoom scope in-game, the CompM2 is actually a reflex sight, meaning it offers no magnification in reality.
The weapon appears to utilize a high capacity magazine for the Glock 18/STRYK 18c, despite the real SUB-2000 only being compatible with standard-length ones made for the Glock 17/Chimano 88.
The magazine well of the SUB-2000 was not designed to work with the shelf of the Glock 18's extended magazine. This presents the risk of the magazine being shoved too far up the weapon when reloading and causing a jam.
Despite being based on a carbine that shoots pistol ammunition, the Cavity 9mm is classified as an assault rifle and is the only non-Akimbo 9x19mm primary weapon in the game.
The Cavity has one of the highest assault rifle damage values in the game, equal to the M308, despite being chambered in 9x19mm Parabellum. Its damage readout seems more congruous with the .40S&W variant, but even then it's still much too high for a pistol-caliber weapon.
The Cavity is likely loaded with overpressurized ammunition as indicated by the red-tipped bullets, which could somewhat explain its high damage to a degree, though the in-game value is still much too exaggerated for real +P 9x19mm cartridges.
The Cavity 9mm is the only assault rifle in the game after the Gage Weapon Pack #01 update to be fixed to semi-automatic, with the M308 having this quality before said update, and the only assault rifle in the game to not have access to the Auto Fire and Single Fire mods.
The front post of the iron sights is missing.
The Cavity folds back in half when not in use, though any and all optical attachments are not accounted for, and will clip through the weapon's rear end. This can be best observed during the slow-mo weapon draw upon masking up in proximity of a guard, camera or civilian.