Ok, so there really isn’t a need to sell plasma anymore in the game is there? Sure it gets hot, but the ability to threaten infantry, light vehicles, and monstrous creatures with S7 and strip armor saves with AP 2 along with multiple shots and blast templates is all you need to know.
But how about putting this knowledge into practice on the tabletop?
From the Space Marine perspective we are going to be focusing on plasma cannons in this post as pistols and rifles work very much the same as other assault and rapid fire weapons- the “best” that you can do in rolling the dice is remove models equal to the number of shots fired. Meaning, if I rapid fire that plasma gun, and I hit twice, and then wound twice, I’m going to kill two models unless they are in cover, have an invul save, etc. Mathhammer would further dictate that on average I will remove kill a single model.
But what about a plasma cannon since it uses a template?
Accounting for the hit/scatter and wounds how many remove kills can I get?
And this is where the skill with the cannon comes in.
Kills are directly related to how many models you can get bunched up under that template and then score a hit- and the more bunched up they are the better also accounting for a scatter of sorts.
So how are we going to get models bunched up?
Placement before we get to that…
Many units are removed just based on the torrent of the dice- roll enough of them and a “1” will come up at some point so naturally we want to create a choke point on the table for this to happen, and our opponent wants to approach form an angle where this won't happen.
First give them a reason to approach the choke point like an objective or a clean way to advance without getting hit by a dedicated heavy weapons team and then place a torrent unit in front of that choke point. Now as they approach either in a vehicle or using terrain or another blocking unit they will want to bunch up behind that as to not be exposed to the torrent.
Anticipating this, the plasma cannon units get deployed along the sides of the choke point to give them an angle of fire behind or around the blocking unit/vehicle/terrain.
Other less reliable ways to cause models to bunch are of course destroying troop carrying vehicles, or encouraging a deepstrike, with the possibility of a low run roll when they land, but these are more of opportunities that happen sometimes in a game over direct setups against experienced players.