Face Eater said:
But unless space marines actually have retractable claws or extra arms then that falls under some unknown additional control mechanism, bear in mind that without a mind impulse unit they don't have mental control of everything connected to them, otherwise they wouldn't need a MIU.
Its called the power armour and black carapace. The black carapace is an MIU link between the marine and his armour. It doesn't work with his bolter because the bolter is not part of the armour, but those big ass hands on a lightning claw are actually attached and integrated into the marines armour. If a marine wants an MIU link to something which isn't a part of his armour he's going to need an actual MIU designed for it.
Speaking of the big ass hands, why do you think the blades on a power claw are its heaviest element? Because they are long? Because you watch movies? Pay attention in school for crying out loud. Use a little logic why don't you.
4 blades, each about half the size of normal swords with a little wiring for the power field, no more than 2 or 3 pounds each (and 3 is pushing it). so thats 8-12 pounds out of 66 accounted for.
Where does the rest come from, oh I guess no where.
What about the frame which holds the blades, mounts and interfaces the weapon to power armour, supports the power feeds, and mounts the ceramite outer armour?
What about the ceramite armour?
What about those large power feeds?
What about the mechanical system to retract and extend the blades?
Oh, you didn't think about all that stuff did you? Well I guess since you didn't think about it then it doesn't matter huh?
Finally, I'm not saying the action to retract the blades should not be an action (of course it would never be more than a half action), but no marine would be in an area expecting combat (or even more rediculously in combat) without the blades out and ready to go. The OP example of the marine being attacked in combat and GM saying the blades are retracted makes no sense. The ONLY exception would be the marine was somewhere where no combat was expected (though marines always expect combat, its who they are), the combat just started, and the marine was suprised. In this case the marine wouldn't be able to react anyways so it would be moot. If a marine was anywhere where combat was expected then the blades would not be retracted unless they had to be to do some kind of work with his hand.