At the beginning of a round, each player has a certain amount of time, called "freeze time", that usually lasts 5 seconds to buy equipment. Equipment includes weapons, armor, ammunition, and others. Sometimes, equipment that is exclusively for either team has a foil on the opposing team, such as the AK-47 for the Terrorists, and the M4A1 for Counter-Terrorists.
The BETA releases of Counter-Strike featured left-handed weapons models and the style has been retained through current version 1.6 by Ben Wilder. In the interim, the option of flipping the model over so that it would appear right-handed has become available. However, since the weapon models are direct mirror images, the left and right side of the weapons are reversed. For instance, the forward assist and ejection port of the M4A1 carbine and the bolt and selector switch of the AK-47 appear on the left side of the gun. This is incorrect and rather absurd in reality, as right-handed (majority) users of the guns would be showered with the ejected cartridges of their weapons. It is even worse for bolt-action rifles, since the original left-handed models incorporated a right-hand bolt, which equates to a left-hand bolt when the image is flipped to a right-handed model. The consensus is that the creator of Counter-Strike, who also modeled the original Counter-Strike weapons, could only model right-handed firearms as used by left-handed people. Hence, during the early beta versions of Counter-Strike, the firearms were left-handed only.
The weapons included are the same in Counter-Strike, Counter-Strike: Condition Zero, and Counter-Strike: Source, but the skins and animations are different, as are some aspects of weapons in different versions. Hence, if one plays Source, then the opinions voiced on weapons may not necessarily be accurate.
When Counter-Strike for the Half-Life engine was released as a retail product, many of the firearms, save for the MAC-10 by the now-defunct Military Armament Corporation, were renamed possibly due to legal/licensing issues (e.g. the Desert Eagle .50AE was renamed the Nighthawk) or are omitted entirely (the Glock 18C is renamed the 9mm Sidearm). Counter-Strike: Source for the Half-Life 2 engine continues this, the tactical shield has been removed from Counter-Strike: Source and Counter-Strike: Global Offensive, as it only appears in Counter-Strike 1.6, Counter-Strike: Condition Zero and Counter-Strike: Condition Zero Deleted Scenes.
In Counter-Strike: Global Offensive, weapons are correctly shown either left or right handed. Furthermore, some names of firearms are now accurate.
Weapons in Counter-Strike, as in most first-person shooter games, are not true to their real life counterparts. As a general rule of thumb in the game, the higher rate of fire and larger round capacity a weapon has, the less damage each individual round will do, even if the caliber and barrel length are equal. A fairly even playing field sometimes takes priority over making weapons which are true to life.