Storm Shield and Close Combat Weapon

A model with a storm shield has a 3+ invulnerable save. A model equipped with a storm shield can never claim the +1 Attack bonus for being armed with two close combat weapons in an assault.

Weapons like chainswords, rifle butts, combat blades, bayonets, etc., do not confer any particular bonus to the model using them. Remember that, in close combat, pistols count as normal close combat weapons and so the Strength and AP of the pistol are ignored.