Target priority is a vast, vast topic but it can be boiled down into some easy thought proceses. These obviously won't cover everything but hopefully will provide a better understanding on how you should organise your thoughts pre-game and during the game. This will ultimately lead to better choices on the battlefield and a more effectively run army. We're going to look at some of those easy steps in a two-part series. Part 1 is going to look at the simple math and in a black and white world, help players identify what weapons should shoot at what targets. Part 2 will be a more applied article which aims to implement the knowledge from Part 1 to actual games by identifying threats to your army in opposing lists and applying appropriate firepower to said target to generate the largest chance of success. BrotherLoring has discussed this concept differently in a previous article and I would recommend you give that a read as well.
There are many ways we can cause maximum damage through shooting and two key concepts need to be kept in mind during this phase. Suppression fire and focused fire. Suppression fire is all about stopping as many vehicles as possible from shooting/moving rather than shooting a tank until it's dead. This is where MSU armies really shine as they can cause maximum suppression with minimal wastage of shots or overkill. On the other hand, sometimes focused fire is necessary, particularly when dealing with unshakable tanks or infantry units or when a unit just needs to die. Whilst forcing morale checks on five or six units is great, there is no guarantee that any of those units will flee (at the same time you could have all of them flee). Even if they do flee those units can often rally, turn around and fight again. Focused fire removes this ability as you shoot until the unit is dead. A dead unit can't do anything shockingly (no not even ATSKNF helps!).
With these two concepts in mind there is generally a clear distinction made between tanks and infantry units, though not always. This is very important for target priority purposes and identifying which units are most likely to cause maximum damage and where. Let's look at a few basics.
You want to shoot your most powerful gun at your opponent's weakest armor.
This doesn't mean you shoot your railguns at Land Speeders but rather than shooting your railgun at AV14 Land Raiders or Leman Russes, you aim them at the lower AVs such as Rhinos and Chimeras. Once those are dealt with then yes your bigger guns can go for the higher AVs. During the mean-time you can deal with such armored targets by blocking them or providing poor targets for them to engage. It's all about generating maximum efficiency. What this does is increase your chances of doing some damage. Its much more important to actively damage things than not do any damage at all and by aiming at the toughest targets, this is more likely. But why aren't we shooting the Railguns at the Land Speeders then? Because there are better weapons in an army to deal with this threat such as multiple S6-8 shots from units like Crisis Suits, Rifledreads, Hydras, etc. It's all about causing maximum damage and that means playing the percentages.
Shooting order is important.
This is huge and a catch 22. If you shoot all your high strength stuff first and pop all the tanks but the high AV (unlikely but possible) your lower strength guns aren't operating at maximum efficiency. At the same time...if I've popped enough tanks to make some of my guns less than optimal, I'm happy. Otherwise you need to ensure you are maintaining maximum efficiency for as long as possible. If you've got S10 AP1 guns firing at Rhinos/Chimeras, you can save all the S6/7 shots for dealing with the lower AV. If there are none, at least these weapons have a higher chance of glancing heavier tanks than the guns with higher strength due to rate of fire.
Shooting order is even more important on guns with dualistic roles. Continuing with our Tau example, both Crisis Suits (plasma + missile setup) and Railheads are dualistic units; they are good at both anti-infantry and anti-tank. Both of these units are generally better at taking out infantry compared to tanks and especially compared to the rest of the Tau army (i.e. Broadsides). Against a Mech army it is generally going to be better to shoot the specialist units first at their preferred targets as units who are capable against multiple model types are more likely to be able to achieve maximum efficiency.
Conclusion
These are some really basic and very theoretical concepts and will really become second nature. You can of course shooting your highest strength guns at AV14 (sometimes that's all there is) but it's a gamble. If you don't do any damage you've essentially wasted that shot and there is obviously a higher chance of this happening the tougher the tank is. Sometimes though, that tank or target just needs to die.
In the end this is all about knowing what your guns are effective against and knowing your unit roles. When you know these and know what your opponent's units do and what their defenses are like, your army will operate at peak efficiency.
That being said there are a lot of exceptions to this which we'll cover in the next article. Sometimes you have to gamble and sometimes a unit just has to die, even if it takes your whole army to do it. This can quite often be setup (i.e. sacrifice a unit to TH/SS and then shoot them after they eliminate the sacrifice) or happen due to unfortunate circumstances (poor tactics/dice, etc.). The important thing to remember is these are mere guidelines but once they become automatic thoughts, it will greatly benefit your thought processes and how you use your army on the tabletop.
