Shoot your enemies, I supposed, but reading the description made me wonder ... it says the mechadendrite can be 'used as a reaction' and 'has no optical targeting' and is 'meant for self defence'.

Does this mean you can't use the thing as a, well, a gun, but only in some kind of Reaction way? If you can shoot it as you please, which Talents would you require to at the same time also fire a gun in your hands?

In the Core Book it states that "As a reaction the Tech-Priest may use this mechadendrite as if it were his off hand, but suffers no penalty to hit." This meant that shooting the gun on your 'drite used up your reaction for the round.

The Errata V2 changed this to "...may use this mechadendrite as his reaction for the round or as a Half Action Attack on his own turn, but it can only be fired once per round." So you can either shoot it as your reaction as before OR you can shoot it as your normal action.

Just realised I only half answered...

Obviously you need the mechadendrite Use Talent in order to use it.

If you had Two Weapon Weilder (Ballistic), you would be able to fire the mechadendrite weapon and a hand held weapon in the same round. It is also woth noting that you do not suffer the normal off-hand penalty for firing the mechadendrite weapon, so I would rule that you count as being ambidextrous when Two Weapon Weilding with a 'drite, so your would only suffer -10 instead of -20 to your attacks.

As has been said the "can use as a reaction" refers to the action type as in Full Action, Half Action and Reaction - meaning that a techpriest employing his mechadendrite won't be able to dodge in the round unless he uses one of the "additional dodge/parry" talents.

I believe the "has no optical targeting" means that weapons mounted on the mechadendrite cannot have telescopic sights or lowlite, so they do not gain the accuracy bonuses/range bonuses that these modifications would give. Also, they cannot serve as remote eyes, allowing the tech-priest to shoot around corners with them (although that would make for a great rare mechadendrite weapon for a more senior priest). Red dot sights might work, since they're essentially laser pointers, and wherever the red dot is is where the bullet will go.

Also, they cannot serve as remote eyes, allowing the tech-priest to shoot around corners with them (although that would make for a great rare mechadendrite weapon for a more senior priest).

So? Just use your optical mechadendrite for aiming.

Also a Ballistic Mechadendrite never suffers penalties for being an Off-Hand Weapon, says so in the description

Cifer said:

Well, sure, if you're going to be logical about it....