I have tried looking through the rules reference and the forums and I cannot find a for sure answer to my question regarding grenades.
To my understanding if I have a core unit of troopers with 1 extra trooper and/or 1 heavy trooper attacks with any type of grenade, the total attack dice for that is based on the total number of troopers involved in the attack, 4-6 grenade dice for that attack. My question comes from after all this. First, if I use Impact Grenades, does the effect of the grenade card stack per each grenade dice involved in the attack? Impact 4-6? Second, once I use the grenades from my one unit in that attack, are the grenades lost or can I continue to use them again and again and again, once per unit per round of course?