We have painstakingly added a TTK stat for weapons on their pages. This is based off the assumption you never miss, never stop, and the distance is the weapon's best range (no damage drop).
Also bear in mind that if distance is involved, there may be fluctuations in the real result (i.e. Homing Missile may need extra time to chase a Jet).
TTK is based on the very first shot hitting the player. If it kills them on the spot, the TTK is 0 seconds. If it does not kill in one hit, the TTK will show how much time that player has to react. For most weapons this should be a very small number that's less than 1 second (like 0.2 seconds if you land all head shots with the SMG).
This is also fairer on a weapon with slower projectiles, like the VSS. You can fairly compare the VSS and SMG since the initial travel time is removed and we only look at what happens once the first shot has hit.
TTK does include reloads. For example the AK SMG will need to reload 9 times when killing a Tank. If it takes 1.65 seconds to reload each time, that's a little over 14 seconds JUST spent reloading. This will mean you can fairly compare which weapons are best for which vehicles.
Enjoy 😄