I don't see where the issue is here.

If you are attacked without your weapons drawn, you cannot parry with them. What makes Lightning Claws a special case?

BYE

Because unlike a sword, you don't take the four blades off the big hand they are attached to and stick them into a scabard when not in use.

In most cases they wouldn't likely even be retracted. At best they would only be retracted when needed. And its very possible the auto-reactive responses from the power armour would do this automatically in many cases. From how it was described it seems the OP simply wanted to get a hit on one of his players and arbitrarily decided lightning claws are always retracted when not making attacks or actively extended, or were retracted in this one case (playing the players character for him, a no-no in RPGs). It is unlikely a space marine is going to be unready for combat anywhere, though (this does not mean they can't be suprised). It is most likely the claws are almost always ready for action, the only exceptions are when the marine needs to do something and the claws would get in the way.

Driving a tank - retracted
Picking up a rocket launcher - retracted
Grabbing a ledge - not necissarily retracted
Walking around minding your own business - probably not retracted

herichimo said:

The Players accompanied an Inquisitor while he opened negotiations between to warring nations without knowing that one party was infiltrated by Chaos. So the negotiations were only a trap to slay the investigating imperial authorities. The Librarian couldn't sense anything because of a psy-damper so the players where completley suprised and had to defend themselves in close quarters. Of course all weapons weren`t readied because the players didn't want to leave an hostile impression. The charachter in question concentrated all his actions on hitting the attacking Demons with his Bolter because he has a high BS and after the enemy got to close he opt to parry the attack and use his Counter Attack Talent, because he has an equally high WS but never bothered to improve his Dodge Skill.

Herichimo, here and then you leave some helpful marks in the forum, but most of the time you act very offensive telling people what they can't do and pointing out mistakes they only did in your eyes. Nothing against productive criticism but this forum isn't to alleviate stress you might have in real life!

Kain McDogal said:

I hope thath the character in question only had a single lightning claw as a pair of them would entirely prohibit the use of other weaponry. :P

Kasatka said:

Of course, although he tried once to requisition a Heavy Bolter in addition to his Lightning Claw and argued with me that he can use this two-handed weapon, because he only needs the Lightning Claw arm to stabilize the HB and can use the free hand to pull the trigger. This was the main reason we switchted to the alternate weapon stats and after the HB wasn't attractive enough anymore he took a Storm Bolter instead. He is a very combat orientated SM.

Kain McDogal said:

Sounds like he is trying to power game the system - focussing on potentially OP imbalances or broken options over fluff and logic.
GM is logic king so just keep smacking him with it till he learns his place.

Given that the Lightning Claws are directly connected to the nervous system through the Black Carapace, he should be able to ready them as a free action.

That being said, if he was caught flat-footed, he should suffer a major penalty. If I were GMing, the penalty would be on the order of -30 or -40. Additionally, it wouldn't get the benefit of its power-field until his combat round.

*Sorry for the double-post, I can't edit my last post for some reason.*

@Kain McDogal: I've been mulling over the whole lightning claw/heavy bolter situation in my head. Namely, "Why would anyone even think of trying that?" But last night, I was considering what I might do in your place, and it hit me: Allow it.

Now, I need to clarify. Let him select both peices of wargear. Then suggest that he go into the training halls of the Watch Fortress to get acclimated to the new wargear configuration. Then, as he tries to go through some combat excercises, have the machine-spirits of both the lightning claw and the heavy bolter reject him. They would be offended by the presence of the other, implying that they are not good enough at their respective jobs to demand the primary focus in the character's personal arsenal. He would be publicly humiliated within the Watch Fortress, likely taking a small renown hit. He'd then have to select one or the other, and for the next mission or two the weapon would be finicky, still angry at him for the insult.

Cryhavok said:

I really like the idea of overcoming the wounded pride of the machine spirits. The manipulation penalty is also something that could dimish by 5 each rank one gains while using this setup as their primary weapon configuration.

Then one could also impose a penalty after this period if one attempts to use one of these weapons without the other in your arsenal because the machine spirits have grown to like eachother.

Dammit, now I wanna playtest this!