The P90 is a moderately powerful submachine gun available to both of the teams. It is commonly used in close quarters scenarios such as Office or Nuke due to its fast rate of fire. The MP5 is considered better by most players because of the P90's inaccuracy from first two Counter-Strike games, recoil and price, but higher damage compared to MP5. The P90 is still very powerful for a SMG, and it is the second most popular submachine gun. For those reasons, the P90 is commonly seen in small or medium sized maps during public matches.
The P90 is a fairly light weapon. While wielded, the player's movement speed is 245 units per second, meaning they suffer very slight speed reduction. The P90 is one of the many weapons able to shoot underwater.
Enemy players will almost always buy armor, so this weapon can be a good choice to wield due to its armor-piercing ammunition. P90 users have a better chance than other SMG users to pierce through helmet as well.
Spray bullets and aim for the head while strafing to the side while the enemy is at close quarters. The most important factor to consider is getting sufficiently close to the enemy. Use a flashbang or attack the enemy's blindspot(s).
At medium range, crouch, aim for the leg, and start firing continuously. This may lead to a headshot. Also, do not use full-auto beyond close range; you will have a hard time hitting your target due to its high spread.
3 to 5 round burst (by click for 1~2 seconds) should maintain your accuracy, burst firing twice on your target should kill at mid-range without headshot.
At long range, crouch and fire 1-3 round burst, and retreat if the enemy is using long range weaponry.
Crouch to increase accuracy at any range.
This weapon is very ideal in scoring multiple headshots at medium range or closer, due to its fast rate of fire and armor-piercing ammunition. However, this tactic is best performed with a flashbang.
Due to the large mag, you can spray with this weapon on a large group and probably get a kill or two, but don't stay in one point for too long.
If sprayed, aim at the line at the top of the reticule, bullets will usually go around the line making it easy to obtain headshots.
Although this submachine gun is often used for "spray and pray" purposes, due to the high spread and fast rate of fire, it is possible to burst-fire while wielding the P90. This tactic is often implemented when targets are located at medium ranges and if the user is aiming around the chest or neck.
The P90 has an unusable red dot sight, which is featured in every Counter-Strike game until it was replaced by the unuseable iron sight in Global Offensive.
However, the red dot sight was featured in the early betas of Global Offensive. In an update of the game, the sight was eventually cut. Despite this, a Counter-Terrorist operative is seen wielding a P90 with the red dot sight in a menu screen in CS:GO.
In early Counter-Strike games, when the P90 is fired, the ejection of 5.7mm case may be seen, in fact the fired rounds in real life will be dropped from the bottom of the weapon, thus the 5.7mm case won't be seen.
In Deleted Scenes, the player has serveral chance to use the P90, but they are all hidden rather than giving to you at the start of the mission. If you can find 5.7mm ammo, then you should find P90 in that mission.
When used with the Five-SeveN as your sidearm, any shots fired consumes the ammo of both guns, as they both fire the 5.7x28mm cartridge.
In Counter-Strike: Source and older games, the ammunition was incorrectly listed as .338 Lapua Magnum (8.6x70mm); the chambering of the AWSM, instead of 5.7x28mm. Shoulder firing even single shots of .338 Lapua is rather difficult, let alone fully automatic fire. This graphical error on the HUD has been since fixed in an update.