Assaulting from transport question

Does the embarked unit have to disembark prior to assault or can shoot from the transport and then roll for the assault range in assault phase?

note: twinlinked poison shots are always useful

You need to be outside to assault.

And Kabalites rifles are rapid fire that does not allow assault after shoot (even with assault vehicle). Wyches pistols are not worth twinlinking with splinter racks.

It is the way I always played it, just was pondernig on possibilities.. thanx for a quick answer Vas.