Chosen Chaos Space Marines

Models equipped with assault grenades don’t suffer the penalty to their Initiative for assaulting enemies through cover, but fight as normal.

When assaulting a vehicle, each model using Krak grenades can only ever make one attack, regardless of the number of Attacks on their profile and any bonus attacks. Against vehicles, Krak grenades have an armor penetration value of 6+D6.

Units with this special rule are deployed last, after all other units (friends and foe) have been deployed. If both sides have infiltrators, the players roll-off and the winner decides who goes first, and then alternate deploying these units. Infiltrators may be set up anywhere on the table that is more than 12" from any enemy unit, as long as no deployed enemy unit can draw a line of sight to them. This includes inside a building (see page 83), as long as the building is more than 12" from any enemy unit. Alternatively, they may be set up anywhere on the table that is more than 18" from any enemy unit, even in plain sight. 

If a unit with this ability is deployed inside a transport vehicle, it cannot infiltrate. Infiltrate also confers a special outflank move to units of infiltrators that are kept in reserve.