6 days doesn't count as a necro does it
In know no fear
didn't Meros (the apothecary) run around the star ship with weights 'simulating the weight' of unpowered power armour when he was recovering from his wound? When he ran into the remembrancer for reference
That would imply that they can move around in unpowered armour, and perhaps it was even a part of how a marine trained fitness- implying it was a difficulty at least
Also in flesh of cretacia
didn't all the sprockets pop out of Amit's power fist, yet he still managed to biff another astartes a proper one?