How? Default game assumes at least 24" between you and your opponent. Nothing the Space Marine army can move that far and charge.
Well, it does depend a little on special rules but usually it works. In the codexes custom chapter rules one feature, see but not be seen, allows you to pay +3 per model for all tactical and devistator squads to give them infiltration. So, on the typical sized map that uses infiltrators (which most missions do) if you get the first turn the enemy will generally be about 12" away if you placed your men right, allowing you to move six inches then charge.


Correct me if I'm wrong (I have been before) but the staff at my local GW say this is the correct interpritation of the rules.