on page 154 of the core rulebook for Dark Heresy, I quote:
"Ballistic Mechadendrite
... This weapon counts as a laspistol with the Compact upgrade. As a reaction, the Tech-Priest may use this mechadendrite as if it were his off-hand, but suffers no penalties to hit. ..."
This description throws some questions:
- treat as off-hand without penalties: does that mean you can't shoot with your off-hand when using the mechandrite?
- 'as a reaction' usually you may only use a 'reaction' as, well, exactly that a 'reaction' to something. So if someone tries to hit you, in stead of a 'dodge' you shoot??

My personal interpretation would be:
"you can use the mechandrite weapon once per round (in your turn/anytime in the round?), but when you do, you sacrifice your 'reaction' for that round. This effectively means you can wield and use three weapons. If you have already used your 'reaction' that round, you can't use the mechandrite weapon"

wolph42 said:

That sounds right, to me.

ok and the first part, *when* can you use it?

Errata Page 9

The Ballistic Mechadendrite on page 154 states: “As a
reaction the Tech-Priest may use this mechadendrite as if it
were his off hand, but suffers no penalties to hit.” Instead it
should read: “The Tech-Priest 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. The
Tech-Priest uses his full Ballistic Skill for the attack.”

You can use it as a normal weapon, for your normal attack each round.

You can use the mechadendrite as an off hand weapon(without the off hand penalties) with two weapon fighting. This does not give you three weapons to attack with as you only have one off hand.

or you can use your reaction, instead of a dodge or parry, to fire the weapon. Reactions do not happen on your turn.

So you can spend a full round doing something, then as a reaction, after your turn is done, you can get off a single shot with the mechadendrite after someone shoots at you.

the errata... of course why didn't i think of that ...

thanks!

If I use it as my reaction on someone who charges me, can I hit him before he strikes me, afterwards or is it at the exact same moment?

Lets say a near dead cultist charges the Techpriest with a chainaxe, the TP uses his reaction to shoot the cultist (why ever he should do that instead dodge or parry) The strike would kill the TP, the shot would finish the cultist. What happens?
Do both of them die because it's the same moment?
Does the TP die because the cultist strikes first?
Does the mechandrite shot kill the cultist before he can strike?

I would say the Techpriest can shoot the moment the cultist starts his charge action and thus is quicker. Its a reaction after all. But what do you think?

I think it means you use up your reaction for the round to attack with the mechandrite in your own turn, not on someone else's turn.

For instance, you could shoot with a pistol (half action), shoot with the mechandrite (reaction), then move your half speed (half action) and your round is now finished.

If I use it as my reaction on someone who charges me, can I hit him before he strikes me, afterwards or is it at the exact same moment?

Lets say a near dead cultist charges the Techpriest with a chainaxe, the TP uses his reaction to shoot the cultist (why ever he should do that instead dodge or parry) The strike would kill the TP, the shot would finish the cultist. What happens?

The reaction (shot) would take place first. The TP would kill the attacker and survive. There is a high likely hood that the BS of a TP is much higher than his AG and he may not even have dodge. The use of a Parry would depend of your TP's build.

Umbranus said:

No, you can't !

By the rules, all Reactions must be triggered by a precise event.

For instance, Dodge and Parry can only be used by a character targeted by a successfull attack.

Other example : When you successfully hit an opponent in an all out attack, Furious Assault allows you to trade you Reaction for a new all out attack.

So, as the errata seems not very clear about what triggered a mechadentrite Reaction, it could mean that it can be used in the same way as Dodge or Parry or it can be use after making your actions for the round.

IMO the second option is the most worthy.

Indeed, when using it like a Dodge or Parry, it would mean that you must be successfully hit (and so hurt) before firing.

EDIT : At best, your opponent makes his charge, rolls to hit, scores, then you roll for your shot and, then, both apply damages.

For instance, you could shoot with a pistol (half action), shoot with the mechandrite (reaction), then move your half speed (half action) and your round is now finished.

I don't think either.

As the rules state that a Reaction must be triggered, they also state that it can't be used in your turn.

So, a Reaction can only be used in response to an other character action or following all your actions for the round.

In other words, you could shoot with a pistol as a half action, then move at your half speed as an other half action and, only then, use your Reaction to shoot with a mechadentrite.

Sorry about necroing a topic ... But was it resolved what types of attacks are permissible with the reaction use of the mechadendrites? Is it the same as the basic half attack? Can you use semi or auto? Can it benefit from a red dot sight?

Thank

schreier

I would say you could theoretically react to anything.

Dodge and Parry require that you be reacting to a *hit*. An attack with the mechandendrite could just easily be made in reaction to a *miss* or a move action (as well as any other action that is taking place ex. a npc attempts to detonate an explosive killing your group, but is shot and killed before he can).

In the example of a charge I would allow one to react to the movement and fire.

If the TP missed and the charging character succeeded in their attack roll scoring a *hit* I see no issue.

If the TP hits and the charging character doesn't dodge (this would interupt his attack), but survives he gets to finish his attack scoring a *hit*.

A weapon attached to the ballistic mechandendrite (a misnomer really since with the right talent you can affix a melee weapon to it) receives the same benefits as any other weapon would reddot, WS bonus etc.

Reaction attacks allow players to perform extraordinary feats, and there are only a few ways to obtain them. Downplaying their abilities in my opinion does them an injustice.

Per the Errata it is limited to a standard half action attack only which rules out the use of semi/full auto during your turn and it can only be fired once (reinforcing the single shot/swing).

My thoughts..

If we're stringent about the fact that a reaction can't be used in your round, then how does Furious Assault work?

You spend a reaction during your turn to make a second attack.

Our tech-priest usually aims (Half), fires his main gun (Half) and then fires his ballistic arm (reaction). Nice and clean, fair (as he can't dodge or parry), and doesn't have to deal with the messy RAW of only being able to shoot as a reaction and stuff like that.