Hello all.

I've recently begun using a second squad of assault marines in my games, and I thought I would post a few of my thoughts here. They seem to work very well for me, so I thought I would spread the love and tell people of my ways, for I see so very few Assault Marines in people's lists. Anyway, on to the meat of it:

Why Assault Marines?
My assault marine epiphany began when I was teaching a friend of mine the game, and I was building intentionally underpowered lists. One unit that kept making it in, of course, was Vanguard Veterans with jump packs. After a few games, I started to notice something.

These guys are good.

Not in a kill everything kind of way, not in an opponent-can't-deal-with-them kind of way, but in a nice all-rounder kind of way. Of course, like hell I'm paying 30 points per guy in a standard list, but lucky me they have a little brother: the humble assault marine. Decent melee, shooting that should not be underestimated, and balls fast, I had found a unit that really does encompass that "fast attack" role. IN addition, they seem to have a bit of a crappy reputation, so even veteran gamers tend to underestimate the havoc they can wreak.

Le'ts start by discussing their most important asset:

Mobility
Assault marines are a lot faster than people give them credit for. Here's a few things to keep in mind when selecting them:
1.) Always give them jump packs. The "free" Rhino, Razorback or Drop pod you can take in its stead simply slows them down, as you have to maneuver around terrain and can't deep strike in the first two, and you lose additional mobility after a deep strike with the pod. Suck it up, take a ten man squad, and realize you'll lose a few on the way. That's 40k.
2.) Jump packs are FAST. Remember, it's a 12" move that ignores terrain. Something I find a lot of players forget: jump troops are allowed to jump into impassible terrain, as long as the model can stand on it. Sure, there's a dangerous terrain test, but it's worth it to lose a guy or two to stay out of the enemies sight until I strike, or close with them at a speed they can't deal with.
3.) That speed, along with their ability to deep strike if need be, means they almost always get to be the ones charging. This is especially important against Orks.
4.) It also means that they get to choose who they want to charge, and "bubble wrapping" units and trying to hide them is less effective against assault marines.
5.) Because of their extreme mobility, it's very easy to multi-charge enemy units. Especially with Shrike, positioning becomes a snap.

For those of you who understand the importance of mobility, battlefield control, and who prize the ability to strike at key targets, I'm sure I have your attention. Of course, how you equip them is important as well. Let's go over the options:

Wargear and Options
1.) A powerfist is mandatory. Mandatory. Thunder hammers also a decent choice, and the obvious replace meant if you are running Vulkan. (Reroll one miss is effectively +1 attack! Hells yes!)
2.) You generally want to take all 10 men. You will take casulaties, and you want them to stay effective. Squads of less than 7 are very unwise.
3.) Because you are taking a powerfist, you will never take meltabombs. You will also never take a combat shield, because it's next to useless.
4.) Lightning claws are not a good option. You need at least a bit of versatility in your squad, and you NEED to be able to bust tanks.
5.) A storm shield for your Sergent is discretionary. You may take one thinking that you will be able to deflect lascannon shots with it, but it's not worth risking your big damage dealer to do it. It can be worth it against some enemies like Tyranids, to keep the sergeant alive and kicking *** long enough to beat up monstrous creatures, but in an all comers list it's not the best choice.
6.) Flamers are decent, and should be your go-to with Vulkan, but I find that they are often overkill. Except on huge light infantry squads, like an orks boys mob, they tend to be unnecessary, as you can kill whatever it is you want to attack by charging it instead. Against heavy infantry like marines, it just isn't that deadly.
7.) Plasma pistols are underutilized and fantastic. Not only do they give you the ability to preemptively kill off enemy heavy units before an assault, but they give you a measure of anti-vehicle firepower. An assault squad with three plasma pistols can easily sink the shots into the side armor of a chimera, and nothing is sweeter than when it explodes and you get to wail on the guys inside. Beautiful. It is true that plasma pistols are an expensive choice, however, so you'll want to playtest with both weapon options before settling on one.

Tactics
The often-quoted Sun-Tzu:
The army's formation is like water.
The water's formation avoids the high and rushes to the low.
So an army's formation avoids the strong and rushes to the weak.
Water's formation adapts to the ground when flowing.
So then an army's formation adapts to the enemy to achieve victory.

This is the approach you should be taking with your assault marines. In fact, it's the approach you should take with all your marines, but that is for another time. The point is this:
Assault marines are fast.
Because they are fast, they only have to assault the things you want them too. If you don't want to fight something, you can easily run away from it, and engage elsewhere.

This makes them very potent backline-slayers. Artillery, tanks, heavy weapon squads... anything your opponent wants out of assault, the assault marines are masters at getting at. And how! They may seem average on paper, but I guarantee you'll swiftly change your tune after they wipe your second long fang squad.

Remember, as well, that your squads don't have to fight. If you don't have a special character, combat tactics is your best friend, allowing you to hit and run the things you actually want to get at.

The other important thing to keep in mind is that this mobility allows you to localize force. It's easy to get your assault marines into assaults with other units in your forces, turning a narrow victory or outright loss into a win.

Deployment
The final thing I want to talk about is also the first thing you do in a game: deploy.

This is the part where most people screw their assault marines. This is the checklist for things to look fro when you deploy:
1.) Is the enemy fielding AP3 artillery? Will I be able to shoot at it/disable it first turn? Is it coming in form reserve?
If it's on the table, and you think you can neutralize it with shooting, start your marines on the table. If it's in reserve, start your marines on the table. If you can destroy it, put your marines on the table. If you can't, deep strike. Templates make foot squads go away.
2.) Is my opponent Chaos, other Space Marines (any variant), With Hunters, Dark Eldar or Tau?
If this is yes, deep strike. Against these armies, you need to strike at vulnerable spots as they appear, and if you start your marines on the table they will spend their first few turns waiting for something to happen. Better to deep strike and take advantage of weakened areas than to leave your guys out in the open until they appear.
3.) Is my opponent Daemonhunters, Eldar, Imperial Guard, Necrons, Orks, or Tyranids?
If this is yes, you can generally start on the table, though be mindful of artillery. These armies will want to get in your face, so use your assault squad(s) on your flanks to kill weak elements, and help squads deal with larger units that you can't spare your elite troops to deal with.
4.) Is my opponent's army built with an element that pushes forward, that is supported by rear elements like artillery, heavy weapons squads, long range tanks etc?
Deep striking makes these units life a living hell. Being able to deep strike an assault squad next to a basilisk, or in back of a Leman Russ, and disable it with plasma pistols long enough to attach grenades next turn is a thing of awesome beauty. Remember, they can't run from you, you're balls fast. The primary melee element of your opponents army will be out of position, so you have free reign of the back field. Enjoy it.

In addition, if you are deep striking, remember not to deep strike next to a heavy weapons team that can toast your assault squad. I am enraged by the number of times I've seen people deep strike next to a huge plasma cannon squad, and get vaporized. YOU HAVE AN 18" ASSAULT RANGE. USE IT. Deep strike out of sight. In cover. Behind an immobilized tank, something, anything. 18" is huge, and you'll get where you're going.

I hope that this article has been helpful to you, and I'm curious as to your thoughts. So, what do you think?