One of the most confusing things about a hunter's repertoire of spells is the exact use of Auto Shot. This ability is unlike the abilities of any other class, quite different from a warrior's swing timer, or a caster's wand shooting. Auto Shot is like a metronome, and the music of hunter DPS requires that we play according to its beat.
We've discussed Auto Shot a little bit in last week's introduction to Shot Rotation, but Auto Shot is much more complex than is first apparent from simply reading the ability's tooltip. First of all, there is a discrepancy between what the interface shows you of Auto Shot and what is actually going on. If you don't use any hunter addons, you may have great difficulty getting a feeling for any of what this article is about, because Auto Shot doesn't have any representation in the default UI. If you use an addon like Quartz or ZHunterMod, however, you'll be presented with a timer that looks something like a regular casting bar -- and while this Auto Shot bar will help a great deal, it is still not complete. No matter what, your imagination and inner sense of timing are going to have to do a good bit of work in getting your shots timed right.
Picturing Auto Shot
Pictured on the right is the little Auto Shot bar I have set up on my computer. Here, Quartz is telling me that I have a 2.2 weapon speed, and I have 0.4 seconds left before my next Auto Shot. I used to see this timer and think that Auto Shot goes off regularly every 2.2 seconds or so no matter what, but this is not exactly correct. Actually, Auto Shot has a 0.5 second casting time (just like Multi Shot), which is not displayed anywhere with any addon that I am aware of.
The first apparent purpose of this short casting time is to help limit hunters' damage while moving, to force us to stand still in order to do damage. It also forces us to time our shots more precisely, however, as anything we do during that half-second will cause the casting time to start over. Anything from short movements to instant abilities like Arcane Shot and even Kill Command can reset the Auto Shot casting time, and can potentially cause a delay of up to a second or more.
So in order to time our other shots right, we have to get a very clear picture of when this hidden casting time takes place. To the left is what the true casting bar would look like if you only cast one Auto Shot, and both the casting time and waiting time were properly displayed.
When two or more Auto Shots are strung together, however, the half-second casting time fits in right at the tail end of the previous Auto Shot's waiting time. You can imagine them as a cascade of Auto Shot waves, one beginning just as the previous one finishes.
Auto Shot and latency
All this is very important because, in some ways, Auto Shot is the best spell you can cast. Not only is it the only damage you get for the exact cost of zero mana, but all you have to do to let it go off again is stop doing anything else for half a second. It also goes off independent of your computer's latency. As computer-savvy people put these things, the Auto Shot timer is entirely server-side, not client-side, meaning the timing of it actually takes place over there in Blizzard land, not on your own computer. As you'll notice if you ever have any huge latency spikes, your other spells like Arcane Shot and Steady Shot may seem pretty much locked down, but Auto Shot will go off quite happily on its own -- perhaps by the time your connection speeds up again, you'll find your enemy has died because of your Auto Shots alone.
If, like me, your connection sometimes has variable latency, such as 200 milliseconds one moment and 700 milliseconds the next, Auto Shot timer may seem long one time and short the next. This is a situation in which having your own sense of internal timing is very useful. Even if your Auto Shot isn't displaying exactly right, you can still have a good sense of how often it should be going off, and just touch other special shots whenever the right time comes, regardless of what you see in the display. You can't be sure that everything will go off exactly right, but you can at least be sure that you are doing your best with the internet connection you have been given.
Latency is the bane of any class. Some classes find that big latency spikes can completely lock them down and prevent them from being useful in any way at all. Rogues, for instance, have automatic swings similar to a hunter's Auto Shot, except that these swings only take place as long as the enemy is in melee range. Latency can cause all kinds of confusion when the enemy moves around and can prevent these automatic swings from hitting at all.
As hunters, on the other hand, your Auto Shots will likely still hit in such situations, but your damage won't be nearly as optimal as it could be with good latency and good timing. In fact, with variable latency (like mine, sadly), it may be extremely difficult to predict when you should cast your next ability so as to not interrupt or delay your Auto Shots. As long as your latency is steady, however, you can usually time things appropriately by just factoring in your delay time and pressing the button for your special shots a little bit early (as portrayed in Quartz with a red section of your casting bar).