Codex Marines can be one of the more challenging armies to field against a true assault army, but there is LOTS of hope for you I assure you! :-)

Because Codex Marines have comparatively good assault against many armies a lot od players are tempted to shoot some and then try to handle assault armies in h2h but this is a serious mistake! You really do want to shoot them as much as you can - and then pick off whatever is left with even more shooting, assault should be your last option - and then only do so when you can seriously overpower them!

For starters - assault armies will often come running toward you, so hold your ground. In this case patience really IS a virtue! :-)

Shoot their transports, or their fleet of claw units (and don't forget Raveners!) - generally all assault armies have their "first wave" elements (the assault elements which will hit you first) these are the people you want to reduce first. If they are using transports it's often fairly easy. If they are naturally fast creatures they are often somewhat delicate so you can drop them if you devote enough firepower to the project.

Once you have slowed them down you can pat yourself on the back (but only for a second!) because you've just bought yourself a little time! Now you need to focus on reducing their numbers (for I assure you they are still going to come toward you! Hold your ground and shoot. Mobile shooty armies (Eldar players and Tau I'm talkin to you!) feel free to scoot back and keep shooting - you want to delay us from hitting you (and keep shooting!) as long as you can!

Generally keep this up until the assault army is gone :-)

It is very true that not all scenarios really let you do this, but this is the best way for you to fight assault armies. If you remember this the concept will still help you even in the scenarios where you can't do this as much as you'd like.

It is also true that a few of the scenarios REALLY favor assault armies (but that's okay because some of the scenarios really favor "shooty" armies too!) so towards that issue all I can say is "every dog has it's day"! :-)

If your army is going to get trounced by an assault army (I mean really trounced) it will happen VERY QUICKLY! We assault types (especially the FULL assault variants) really want to get into assault just as fast as possible - so if things go OUR way we'll hit you with our assaults before you can degrade our units and your army will truly be overwhelmed very quickly. This is not because our armies are overpowered - it is because we used our cleverness to maximize our impact (veteran shooty players can often shoot us to pieces!) so when the day comes that you get your clock cleaned by a really assault heavy army just know that it's time for you to refresh you "shooty" tactics and you'll be back in the game in no time :-)

For we assault armies - if we're not in assault by the end of turn two it usually means things realy aren't going our way (although the occassional sneaky pete will be able to pull out a well coordinated 3rd turn assault - but that's truly a rarity, and a dangerous gamble on the part of the assault army!).

One last thing - there are two times that you are in trouble when you are fighting an assault army, this is what those times look like.

1) the assault army is actually using cover - keeping their forces concentrated, and behind cover as they approach you. When the time comes this army will all come running, driving, flying, (whatever) out from cover and overwhelm you with targets - and some of those units will hit you with nasty assaults. If you see this coming you are in trouble because you're fighting an assault army veteran. Try to move your strongest h2h units to the front to make ready for their charge (that or screening units that you want to sacrifice so you can shoot them one more time as they sweeping advance). Mobile shooty armies (Tau and Eldar again) you can try to scoot out and pop a few shots at their transports as they come up - but beware of being shot in return (I coach assault armies to do this all the time!) :-)

2) somehow you're facing an all out rush right from the getgo - (this sometimes happens you know!) your only choice is to kill the transports first, and whittle the assault troops down as fast  as you can - the vehicles and other shooty units are there to distract your fire from the assault units. Sure the shooting units are killing things - but not nearly as much as the assault units will when they hit! :-)

In either situation you are already in trouble, both 1 or 2 can happen either from a scenario or table which favors assault, or from a clever assault commander - either way will mean a special challenge for you (and a really exciting game you lucky duck!) :-)

So there you go - the good the bad and the ugly. I hope it has helped :-)

Glory to the Emperor and Sanguinius ~ Brother Edward

PS. when my assault brothers hear that I told you what's what, tell them for me that I didn't want them getting soft!  hahahaha :-)