What Strength to Use

In almost all cases, when rolling to wound in close combat use the Strength on the attacker's profile, regardless of what gun they are using. Some (but not all) close combat weapons may give the attacker a Strength bonus. In a unit containing different Strength models roll their attacks separately (they'll quite often have different Initiative characteristics too). So, for example, in a unit of Gretchin with an Ork Slaver, the Grots' attacks are made with their puny Strength of 2, but the Slaver's attacks use their more macho Strength of 3.