Attacks
Attacks in close combat work like shots in shooting – each attack that hits has a chance to wound, the wounded model gets a chance to save, and if it fails is (generally) removed as a casualty. Each model base-to-base with an enemy model strikes with the number of Attacks (A) on his characteristics profile. In addition the following bonus attacks apply.
+1 Two Weapons. Models in base-to-base contact with an additional close combat weapon or pistol in each hand have an extra +1 Attack. Models with more than two weapons gain no additional benefit – you only get one extra Attack regardless of whether you have two or more close combat weapons.
+1 Charge. Models in base-to-base contact who launched the close assault that turn (ie charged) get +1 Attack on their normal profile for that turn only if they did not fire in the shooting phase. Models belonging to units which fired in the shooting phase do not receive the charge bonus.
Exception: Models such as Terminators, Bikes, Dreadnoughts and Walkers which always count as stationary when firing always receive the charge bonus whether or not they fire before entering close combat.
Models not touching an enemy, but within 2" of a model from their own unit that is touching an enemy, may make one Attack regardless of their profile, armament or whether they charged.
Designers note: This is another important change, under the previous rules there was seldom any good reason not to charge into close combat in order to get the bonus attack for charging (do it to them before they do it to you). This change means that troops well armed with guns may be more inclined to stand their ground and shoot, leading to more short-ranged 'firefights'. Units using flamers and other short ranged weapons must weigh up the benefits of shooting over getting an extra attack in close combat.
Rolling to Hit
To determine whether hits are scored roll a D6 for each Attack a model has. The dice roll needed to score a hit on your enemies depends on the relative Weapon Skills (WS) of the attackers and their foes. Compare the Weapon Skill of the attackers with the Weapon Skill of their opponents and consult the standard rulebook Weapon-Skill-comparison to-hit chart to find the minimum score needed on a D6 to hit.
Example: A unit of five Space Marines fighting five Eldar would roll five D6s for their attacks. If they were charging and did not shoot in the shooting phase they would roll ten D6s (1 Attack +1 each for charging).
Attacks should be rolled together where the same to hit roll is needed — this approach saves time and speeds up the game when you've got several big close combats going on at once. In the example above therefore the Space Marine player would roll his ten attacks together.
Hitting Units With Different Weapon Skills
Many units in Warhammer 40,000 contain models with different levels of Weapon Skill. Attacks against a unit are resolved using the Weapon Skill of the majority type in the unit. For example, a mob of twenty Grots (WS2) is led by an Ork Slaver (WS4) — while the Grots are in the majority, attacks against the unit are resolved using their WS of 2, however skilled the Slaver is he can't prevent the Grots getting hit in the first place. If there is no majority Weapon Skill type use the lowest Weapon Skill in the unit.
When models attack, calculate their own to hit numbers based on their own Weapon Skill. If the Grots and Slaver hit back at their enemies, the Grots' to hit number will be based on a comparison of WS2 with the enemy WS, the Slaver's on a comparison of WS4 with the enemy WS.
Allocating Attacks
We simply assume that the warrior is contributing his shots and blows to the swirling combat going on. This means we don't have to worry about whether individual models strike their respective opponents in base contact.
When a unit inflicts hits they may only affect enemy models who are in contact with them or who are within 2" of a model that is in contact with them. These are the only enemies able to strike back at them so it is reasonable that these are the only ones who can be hurt. If all the enemy models in the 2" 'danger zone' are slain any excess wounds are lost.
Remember that attacks are resolved in initiative order, so it's possible that all the available enemy may be slain before some models get to strike.