A popular debate amongst the counter strike community is whether a large or small crosshair is more effective in killing your targets. Let’s just say that a lot of misinformation goes around and I’m here to set things straight and give you the skinny on some of the advantages associated with each size.
Ordinarily you must adjust the crosshair scale under Options -> Multiplayer

There are three options: Small, Medium, and Large. However, users can manually adjust their crosshairs to fit their particular play style by using the command cl_crosshairscale.
Cl_crosshairscale
A user can manually adjust their crosshair size by typing cl_crosshairscale and then a numerical value between 1 and 3000. Most of the time crosshairscale is only useful between 500 and 2,000 and is heavily dependent upon screen resolution. The following pictures show the same crosshairscale under a 640x480 resolution versus an 800x600 resolution.


The various crosshair sizes also have psychological benefits that may interest you. I will group them under the Large, Medium, and Small categories.
Large Crosshair: The larger crosshair has several advantages and disadvantages. The crosshair is easily visible and losing it in the middle of a firefight is very difficult. The crosshair is also ideal for spraying because the northern crosshair line is easily visible and much of spray control is dependent on how well you place this line over your target. The downside, however, is that the initial bullet of every gun will land directly in the center of your crosshair. Consequently, the large crosshair forces the player to visualize where the very center is and adjust as the subsequent bullets are fired. Instead of aiming with the center of the crosshair, use the east and west crosshair lines to establish the center and wrap them around your target.
Medium Crosshair: The best of both worlds, the medium crosshair is noticeably smaller than the larger crosshair, enabling the user to determine the starting point of a spray, but still large enough so that using pistols may be difficult for a new player.
Small Crosshair: The small crosshair is conducive for pistol usage. With a small crosshair, a player simply has to point and click with a pistol and with great accuracy knows where the bullets will land. Weapons like the colt function excellently with the small crosshair since the first two bullets land directly in the center of the crosshair, making the use of two bullet bursts excellent for headshots. The disadvantages of the crosshair include it’s visibility and spray management. A player may easily lose track of where the crosshair is on screen, especially in brightly lit areas. Spraying also becomes more difficult because of the slight jostling of the crosshair lines. Managing longer sprays that include anywhere between four to six bullets become more difficult to manage and require a sort of visualization opposite of the large crosshair. Instead of having issues with where the center of the crosshair is, the user must estimate how high the spray is climbing, as it is harder to trace in the small crosshair.
The Dynamic Crosshair
Enabling dynamic crosshair causes the crosshair to fluctuate depending on the player’s movements. I personally recommend keeping the dynamic crosshair off so as to develop consistency and a way of measuring your spray relative to the crosshair. Some people have it on, some people have it off, but the important part is that you try out both and figure out what works best for you.
Changing your Crosshair Color
Under the same option where you changed your crosshair size, you can also change your crosshair to one of several colors including red, blue, yellow, and the default green. Some servers also allow you to change your crosshair to other colors by using the cl_crosshairalpha command to change your colors. The numerical value you place after the command will determine the color of the crosshair.
As you can see, the crosshair scale is more of a psychological issue rather than a fact based issue. What is true and works for one player may not necessarily work for another, so I urge you to experiment and find out what works best for you.
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