Damage spread refers to the fact that a weapon has a spread, or range, of damage that it can deal on any given hit. By default, weapons generally have a +/-10% damage spread.
So if a weapon has 100 base damage, it might do as little as 90 (10% less than base) or as much as 110 damage (10% more than base) on hit. This amount of damage dealt is simply a random value from within the "spread".
Originally, the spread was +/-25%, but Valve eventually reduced it to only +/-10%.
Note that this isn't the only thing that affects weapon damage, there is also a damage falloff based on range for most weapons (they do less damage at greater distance).
Some servers disable damage spread because they think it makes the game more "skill-based" and more fair, since damage dealt is more consistent. This is similar to the argument used for disabling critical hits.
Weapon Spread refers to the random pattern of "spread out" that pellet weapons in TF2 have when fired. As distance increases, each pellet that was fired spreads out.
Some pellet weapons in TF2 include (this is not a full list, more weapons are being added to TF2 pretty quickly recently):
- Shotgun
- Scattergun
- Force-A-Nature
- Frontier Justice
Some servers use a "fixed weapon spread", which means that the pellets still spread out, but do so in a nonrandom fashion, so that each shot is the same.
This is the fixed weapon pattern most commonly used:
This is controlled by the server setting: tf_use_fixed_weaponspreads 1
. Some servers like to use this setting because they feel it removes more luck from the competition and makes the outcome of battles more based on skill.
However, one side effect of making this change is that due to the increased accuracy and reliability, pellet weapons become more powerful than they are normally.
Note that server setting does not have an impact on any other weapons than those listed above.
Some other weapons may appear to have weapon spread, but they in fact do not. They do however have inaccurate firing, and/or recoil that effects how straight a shot will go. In terms of TF2, weapon spread only refers to the situation where multiple projectiles are fired from a single shot, and spread out from each other as they travel.
Best Answer
Here's a practical use for the otherwise rather uncommon event, specific to the TF2 setting. It uses the fact that a disguised spy can use enemy teleporters and perform telefrags on the opposing team when coming out of them. Doesn't work that well on experienced engineers, but can catch inexperienced ones off guard.
This only works if the engineer is near the teleporter exit, turtling behind a sentry that has the exit near it.
As a spy, work your way to the enemy teleporter entrances. They're usually right outside the spawn. Make sure you're disguised and that the teleporter is charged and ready for use. Sap the teleporter and stand over the sapped teleporter before the sapper is removed. If the engineer is standing over the exit as he's removing the sapper (as inexperienced engineers often are), you will immidately teleport through the teleporter as the sapper is removed and will perform a telefrag on the engineer. This strategy also has the added benefit of leaving you disguised and ready to sap all the buildings of the now dead engieer that happen to be near by, including the teleporter you just used.
Some inexperienced engineers might also build these tight clusters of buildings, where the teleporter will be right behind the sentry. In these nowadays rather rare cases you can perform the telefrag without even using the sapper, altough there is a risk of the engineer not holding his place all the time.