I'm really baffled how something broken as this managed to find its way in the Core Rulebook. Coming over from d20 Pathfinder, I thought maybe it won't be as good in the game as it sounds, but it's basically the equivalent of making a Full Attack action as a free action.

For an Adeptus Mechanicus character it's available right from the start and really, nothing's stopping him from just Aiming or even Full Aiming all the time and hitting multiple opponents with Full Auto Burst. He doesn't even have to stop to reload. It just boils down to getting into Short Range, Aiming and shooting. Not even getting some melee combatants in his way is a sure way to stop him, as he can just Disengage and, what do you know, attack them anyway as a free action (he doesn't even get any penalty, because now they're in his Point-Blank range).

Now, am I missing something or is this just one of those horribly overpwered things carried over from the previous edition (it's practically copy/paste from Rogue Trader version) and in need of a houserule to tone it down?

I second the "need" to houserule a nerf for it. Like you said, it completely distorts combat. At the moment, I don't have anything to offer, but I'll let you know if that changes.

I never really saw the issue with it, other than I'd personally add the necessity to have pre-existing Mind-Impulse Unit installed beforehand. It should probably be a weapons upgrade and mounting, more than anything else.

The only solid change I can see that would make sense is really just a penalty to hit if you move in the same round.

Aren't MIU-controlled weapons on NPCs usually Pistol-types and other small weapons that can actually fit on a shoulder mount? Excepting certain Mechanicus cyborgs with MIU-linked Heavy weapons?
The easiest way to houserule this would probably be to limit it to Pistols. Hitting a lot of people with Full-Auto Burst is a powerful feature, but from a Pistol it is not more powerful than your average Psyker or rifle-wielding murderhobo.

He doesn't even have to stop to reload.

Why not ? it doesn't eliminate clip size and most guns' reload time is 1-2 Full.

Unlike the more advanced MIU version normally only granted to priests of the Adeptus Mechanicus, this model is more simplified, allowing the user to remotely operate a single weapon which is attached user’s body. While not as elaborate, it is easier to use and a favourite of many militant professions. This system allows the user to fire the linked ranged weapon as a Free Action during his turn. Note that he can still only take a single Action with the Attack subtype during his turn. This additional weapon must be connected to the user via the MIU weapon interface, and is usually equipped as a shoulder mount.

Taking the following into consideration:

It is Rare (Average for PCs with "Replace the Weak Flesh")

It requires that a weapon is attached to the user's body. That severely limits the types of weapons which can be linked.

Tech characters seldom get a high BS, if they do, kudos for spending lots of XP to make an atypical character.

I find it to be quite balanced, as anyone sporting the implant will likely draw attention to her/himself - impacting subtlety.

Do they have to be "Tech Characters" though? I think this is an implant that's available to all types of characters without any prerequisites whatsoever.

Otherwise I agree.

Edit: I guess it's because the OP was referring to a Tech Priest character, still, as far as I know it's available to all types of characters without any prerequisites. So balance wise it could be a bit meh. I'd limit it to Pistols as Johkmil suggested.

other than I'd personally add the necessity to have pre-existing Mind-Impulse Unit installed beforehand.

It's not like he can't have both.

Why not ? it doesn't eliminate clip size and most guns' reload time is 1-2 Full.

Rapid Reload takes care of that and even if it's a full action, he can still fire as a free action.

It requires that a weapon is attached to the user's body. That severely limits the types of weapons which can be linked.

How so? I can understand that Heavy weapons couldn't be attached, but Basic are fair game, as far as rules indicate.

Tech characters seldom get a high BS, if they do, kudos for spending lots of XP to make an atypical character.

They don't even really have to spend a lot of XP. If he, for example, takes the role of the Assassin, the combination of aptitudes will still allow him to fullfil the tech role and allow him to invest in BS easily.

Question: What is the largest weapon that can be used with an MIU?

Answer: This depends on where the weapon is mounted. If on the shoulder, for instance, it is likely that only a Pistol weapon could be used, as anything larger would be too heavy and unwieldy. In general, only Basic and Pistol weapons can be used with MIUs, however if the Explorer found a way to mount a heavy weapon on a mobile platform or vehicle (and didn’t mind being linked to said weapon) he could install an MIU on it.

-Rogue Trader Errata 1.4, Page 12 on MIU Weapon Interfaces

The "official" (I use the word lightly) stance on weapon class restrictions. The linked weapon doesn't have to be attached at the shoulder; a Basic weapon might be attached to the arm or hip instead.

When balancing a player-obtainable (for lack of a better word), I consider the best-use cases. For the MIU Weapon Interface, one such case would be some schmuck with a Sniper Rifle or other Accurate weapon Full Aiming and blasting away in the same turn. Pulling other books into the mix, even Pistols can benefit from Accurate's extra 2d10 (thanks to an {Only War} Talent). The main problem is the Full Aim + Standard Attack relationship, though there are also things like sustaining Psychic Powers but being able to attack anyway.

Taking the following into consideration:

It is Rare (Average for PCs with "Replace the Weak Flesh")

It requires that a weapon is attached to the user's body. That severely limits the types of weapons which can be linked.

Tech characters seldom get a high BS, if they do, kudos for spending lots of XP to make an atypical character.

I find it to be quite balanced, as anyone sporting the implant will likely draw attention to her/himself - impacting subtlety.

Availability is not a balancing factor in this case, as Rare (or Average) items are well within reach early- to mid-game. If the base Availability was Extremely Rare or lower, then Availability could be considered.

Limiting weapon selection doesn't solve the issue of a Free Action attack.

Why exactly would a Tech character not want to get high Ballistic Skill? If anything, I figure they would be one of the more likely candidates to do so, what with their knowledge of weapon technology and all. And there's Tech-related gun support through Talents and such.

Saying the MIU Weapon Interface is "gated" (which it's not) by Availability, weapon selection, and/or a Tech character's BS is a weak argument to me. Hiding a cybernetic behind conditions and prerequisites doesn't stop it from being unbalanced.

I personally always considered shoulder-mounted weapons limited to Basic, and wrist-mounted weapons limited to pistol.

Limiting factors to this that I would consider appropriate and make sense would be:

• Increasing reload time; it is hard to reload something that is mounted on your back. It's a small factor, but I'd like to add it. At the very least, a Full Round Action added to Wrist-Mounted (Pistol) weapons and two or maybe even three to Shoulder-Mounted (Basic) weapons.
• Increasing the cost. This is something that has been totally lost post-Rogue Trader, but costs were balancing factors aside from Availability. The removal of relative equipment costs and values means that anything in the same bracket is equally obtainable (rules-wise at least) to everything else in the same Availability bracket. Which is of course utter rubbish. While an MIU Weapons Interface might not be particularily rare (and I don't think it should be), it should be expensive, or have a note on it being fairly restricted access outside of proper channels.
• The Aim Action(s) should have a little note saying that you can't Move, Aim and Attack in the same round. You may start an Aiming action after Moving, but you may not move before or after Aiming.
• Installing a Weapons MIU Interface should require already having a Mind-Impulse Unit installed. It makese absolutely no sense otherwise. A Weapons MIU Interface is really just the equipment for mounting and controlling a weapon through a Mind-Impulse Unit. Either you have an MIU or you don't.

Aside from that, I really don't see it as that much of an issue, and my "restrictions" are more "makes sense" than actual balancing efforts. This is an "issue" that has never cropped up in any of the games I've been in.

Moving and Attacking isn't really that big of a problem, is it?

I personally always considered shoulder-mounted weapons limited to Basic, and wrist-mounted weapons limited to pistol.

Aside from that, I really don't see it as that much of an issue, and my "restrictions" are more "makes sense" than actual balancing efforts. This is an "issue" that has never cropped up in any of the games I've been in.

Moving and Attacking isn't really that big of a problem, is it?

I mostly agree with everything you listed.

I consider "wrist-mounted" and "arm-mounted" to be different things. A wrist-mounted weapon might jut past the hand, but never takes up more real estate than the forearm. Taking from {Rogue Trader - Hostile Acquisitions}, the [Weapon Bracing] cybernetic is an example of what I would consider to be an arm-mounted weapon, numerous supports and structures running from hand to shoulder holding the weapon in place.

Aim actions are already interrupted by taking Move actions as written (or at least implied), but Move actions aren't part of my considerations.

I have another beef with the MIU Weapon Interface, namely it invalidating the [Move and Shoot] Desperado Bonus and the [Hip Shooting] Talent. There is absolutely no reason to "waste" Experience on a Talent that could be obtained for "free" as part of a cybernetic. Moving and Attacking itself isn't the problem as much as spurning characters who can't take back their Role choice or spent Experience. I've shared these opinions before; they're floating around the forums somewhere.

I have another beef with the MIU Weapon Interface, namely it invalidating the [Move and Shoot] Desperado Bonus and the [Hip Shooting] Talent. There is absolutely no reason to "waste" Experience on a Talent that could be obtained for "free" as part of a cybernetic. Moving and Attacking itself isn't the problem as much as spurning characters who can't take back their Role choice or spent Experience. I've shared these opinions before; they're floating around the forums somewhere.

This is a sentiment I completely share, though. No item/piece of equipment/cybernetic should ever grant a Talent or invalidate an expenditure of experience (at least not completely). There's a couple of Cybernetics that flat-out grant Talents (although I'm not sure about DH2 in itself), such as Bulging Biceps.

I'm not sure what to do about it, though. The Weapons Interface makes sense as it is, and I'd be more liable to change how for example Hip Shooting works or interacts with it.

I would house rule that the desperado can make an additional pistol weapon attack in addition to the MIU attack. If you have Hip Shooting, I would allow you to Aim (+10) even if you took a full action move. Now it doesn't invalidate the talents.

If aiming with MIU is too powerful, add the rule that a Good Quality weapon interface allows you to benefit from half-action aiming, while a Best quality one would allow you to do a full-action aim. That is a fine degree of control over an interfaced tech, dare I say princeps level accuracy. So it makes since it would be rarer.

One aspect of the weapon MIU that I think is worth to take into consideration is that it is almost always the opposite of subtle. Wristmounted MIGHT be concealed under a heavy robe or cloak, but arm and shoulder mounted not so much. Good luck getting entrance to the fancy party with that.

I think the big drop in social utility balances the powerfull battle bonus it provides. That is also why the desperado skill and the hip shooting are usefull. They still allow you to be a socially usefull character.

It's absurd. Really, being able to fire a weapon without occupying a hand is already a powerful enough benefit, the action economy advantage ought to be removed entirely. Having played with this on an admech character in Only War - it's disgustingly good.

I, personally, don't have a problem with it. A very "powerful" option? Sure, it's all kinds of good in a fight. As the description says, though; "...[it is] a favourite of many militant professions". As a player, I'd expect anyone I come up against who's in a "militant profession" to have the potential to have one of these and compensate my own tactics to match if they do. As a GM, I know that I have the liberty to use them against my players. That's the balancing factor; everyone has access to them, much as anyone might have a plasma gun, sniper rifle or other powerful weapon or piece of equipment. If it were only available to certain characters; from a certain homeworld or in a particular role, then it would be unbalanced, unfair or in need of houserules. As it is, it is its own balancing factor.

As for the weapon requiring a "link" and be "attached" to the user, the book states that this is usually in the form of a shoulder mount, but it does not require it to be so. I see no reason why this could not be a hand-held weapon, even a heavy weapon, that the character is carrying and "attached" via a cable or similar connection. The restriction this places upon the character is that he can't discard or arm the weapon in haste, nor conceal it easily. The limitation this places on social scenes is obvious and even just walking down the road so obviously armed will have an impact on your Subtlety, so it's not an auto-include by any stretch of the imagination.

I personally always considered shoulder-mounted weapons limited to Basic, and wrist-mounted weapons limited to pistol.

The Grey Knights wear Basic storm bolters on their wrists, iirc, and the Orrus-type Spyrer suit is dual-mounting multibarrel bolt launchers on its wrists.

Good set of houserules, though! Except for the Aiming restrictions - which may be balanced, but don't strike me as particularly realistic (why should a character not be able to move and then aim?).

One aspect of the weapon MIU that I think is worth to take into consideration is that it is almost always the opposite of subtle. Wristmounted MIGHT be concealed under a heavy robe or cloak, but arm and shoulder mounted not so much. Good luck getting entrance to the fancy party with that.

Technically speaking: why should that be a problem? There may be some events where weapons are barred, but from all I've seen, the Imperium is a society where weapons are a status symbol - indeed, going to a party without a fancy sabre or bolt pistol will get you funny looks.

I also had to remember the Predator movies, though. It could be possible to create a mount that lets the weapon rest on the character's back until it is triggered. Sure, it'd still be discernible by anyone who sees the character from the side or the back (you could cover it under a cloak, but that would interfere with extending it), but ...

I personally always considered shoulder-mounted weapons limited to Basic, and wrist-mounted weapons limited to pistol.

The Grey Knights wear Basic storm bolters on their wrists, iirc, and the Orrus-type Spyrer suit is dual-mounting multibarrel bolt launchers on its wrists.

Good set of houserules, though! Except for the Aiming restrictions - which may be balanced, but don't strike me as particularly realistic (why should a character not be able to move and then aim?).

One aspect of the weapon MIU that I think is worth to take into consideration is that it is almost always the opposite of subtle. Wristmounted MIGHT be concealed under a heavy robe or cloak, but arm and shoulder mounted not so much. Good luck getting entrance to the fancy party with that.

Technically speaking: why should that be a problem? There may be some events where weapons are barred, but from all I've seen, the Imperium is a society where weapons are a status symbol - indeed, going to a party without a fancy sabre or bolt pistol will get you funny looks.

I also had to remember the Predator movies, though. It could be possible to create a mount that lets the weapon rest on the character's back until it is triggered. Sure, it'd still be discernible by anyone who sees the character from the side or the back (you could cover it under a cloak, but that would interfere with extending it), but ...

Weapons mounted on the wrist or arms of power armor are well outside the scope of Dark Heresy.

As for subtlety and status symbols: Yes, nobles and such will carry swords and bolt pistols (that they may not actually know how to use) as status symbols . They're not weapons designed to engage actively in heavy combat.

Now, an MIU-WI is explicitly a weapon of war. No one mistakes it for decoration at a party and most people will likely be offput by it.

It would be like taking a missile launcher or a plasma rifle to a party. You can display those at home or discuss them, but you don't take them out of the case unless you're looking to cause some destruction.

Weapons mounted on the wrist or arms of power armor are well outside the scope of Dark Heresy.

Only if power armour is outside the scope of your Dark Heresy game.

Besides, PA is not a requirement to wrist-mount weapons. Technically, would it not suffice to just fit it as a bracer, with a cable connected to the user's MIU?

As for subtlety and status symbols: Yes, nobles and such will carry swords and bolt pistols (that they may not actually know how to use) as status symbols . They're not weapons designed to engage actively in heavy combat.

Now, an MIU-WI is explicitly a weapon of war. No one mistakes it for decoration at a party and most people will likely be offput by it.

It would be like taking a missile launcher or a plasma rifle to a party. You can display those at home or discuss them, but you don't take them out of the case unless you're looking to cause some destruction.

You are jumping to unsuitable comparisons - I don't think people were discussing putting missile launchers on their shoulders. I was specifically talking about status symbols, using the exact same term before you.

Elaborately decorated bolters are rather common with rich people, so why would it look out of place to have one such weapon resting on a shoulder instead of holstered at the hip? Ultimately, all the nobles will care for if it looks suitably fashionable rather than a worn out piece of military equipment. If it looks nice and subtle enough to appear like part of your garb (like a ceremonial sabre), it becomes a piece of decoration.

That reminds me of one of the novels where the Battle Sisters present at a ball were required to place large white "peace ribbons" on the barrels of their boltguns, though. Obviously that doesn't have to mean much, as lack of a uniform canon merely renders such sources a possible suggestion for one's own take on the setting, but this could be a viable way to deal with larger weapons at formal events.

...but this could be a viable way to deal with larger weapons at formal events.

Heh. I just have images now of some hulking, muscle-bound, leather-clad hive-trash at a fancy ball, wielding a missile launcher with a big white ribbon tied around it in a bow saying "Wot? I gots the ribbon ent I? Not fancy enuff fer yoo?"

some hulking, muscle-bound, leather-clad hive-trash at a fancy ball, wielding a missile launcher with a big white ribbon tied around it in a bow saying "Wot? I gots the ribbon ent I? Not fancy enuff fer yoo?"

That sounds like straight out of a Rogue Trader game..

Weapons mounted on the wrist or arms of power armor are well outside the scope of Dark Heresy.

Only if power armour is outside the scope of your Dark Heresy game.

Besides, PA is not a requirement to wrist-mount weapons. Technically, would it not suffice to just fit it as a bracer, with a cable connected to the user's MIU?

As for subtlety and status symbols: Yes, nobles and such will carry swords and bolt pistols (that they may not actually know how to use) as status symbols . They're not weapons designed to engage actively in heavy combat.

Now, an MIU-WI is explicitly a weapon of war. No one mistakes it for decoration at a party and most people will likely be offput by it.

It would be like taking a missile launcher or a plasma rifle to a party. You can display those at home or discuss them, but you don't take them out of the case unless you're looking to cause some destruction.

You are jumping to unsuitable comparisons - I don't think people were discussing putting missile launchers on their shoulders. I was specifically talking about status symbols, using the exact same term before you.

Elaborately decorated bolters are rather common with rich people, so why would it look out of place to have one such weapon resting on a shoulder instead of holstered at the hip? Ultimately, all the nobles will care for if it looks suitably fashionable rather than a worn out piece of military equipment. If it looks nice and subtle enough to appear like part of your garb (like a ceremonial sabre), it becomes a piece of decoration.

That reminds me of one of the novels where the Battle Sisters present at a ball were required to place large white "peace ribbons" on the barrels of their boltguns, though. Obviously that doesn't have to mean much, as lack of a uniform canon merely renders such sources a possible suggestion for one's own take on the setting, but this could be a viable way to deal with larger weapons at formal events.

Okay, I'll rephrase. The vast vast majority of characters will not be mounting storm bolters on their power armor in Dark Heresy. If that is one of the major issues you have with the MIUWI, then I reject it as a problem.

As for shoulder mounting, it seems clear that shoulder mounts are basically reserved for pistol-class weapons. It seems that the concern of this thread was taking advantage of the MIUWI for larger weapons. If your ballroom attire includes a sleek shoulder-mounted bolt pistol, then perhaps that's within reason, but we are entering well into the realm of DM fiat here. e.g. What kind of gun culture does the planet have?

For larger weapons, I think they would be even more out-of-place at any non-combat event when mounted as an MIUWI.

Okay, I'll rephrase. The vast vast majority of characters will not be mounting storm bolters on their power armor in Dark Heresy. If that is one of the major issues you have with the MIUWI, then I reject it as a problem.

The vast vast majority of characters will not be using MIUs in general. Does that really make the discussion invalid in your eyes?

I think that of the people who do use MIU "gun slots" in the first place, a rather large number would go for basic weapons rather than pistol ones, as to me it seems a bit silly to go for such an obvious increase in potential firepower and then intentionally use the smallest possible weapon for it.

As for shoulder mounting, it seems clear that shoulder mounts are basically reserved for pistol-class weapons.

Not as per this game's default rules, and not by from what we have seen elsewhere in the IP.

As for shoulder mounting, it seems clear that shoulder mounts are basically reserved for pistol-class weapons.

Not as per this game's default rules, and not by from what we have seen elsewhere in the IP.

There was a post somewhere by Tim stating that shoulder mounts would effectively only hold pistol-class weapons. From the FAQ:

"Question: Can a heavy weapon be mounted with a Mind Impulse Unit (MIU) or MIU Weapon Interface (page 184)?

Answer: Yes, though the user would have to perform the Brace Heavy Weapon action as normal. Depending on the size or shape, it could however impart penalties to the user’s Agility and the warband’s Subtlety at the GM’s discretion."

So, this clearly leaves room for houseruling and makes it clear that the MIUWI rules are incomplete (probably purposefully, see below).

Of course I can't findthe post about pistol weapons. *shrug*

As for your pictures (I like them!), I can't tell what kind of weapons those are easily. The second one looks like it could be a handcannon.

Okay, I'll rephrase. The vast vast majority of characters will not be mounting storm bolters on their power armor in Dark Heresy. If that is one of the major issues you have with the MIUWI, then I reject it as a problem.

The vast vast majority of characters will not be using MIUs in general. Does that really make the discussion invalid in your eyes?

I think that of the people who do use MIU "gun slots" in the first place, a rather large number would go for basic weapons rather than pistol ones, as to me it seems a bit silly to go for such an obvious increase in potential firepower and then intentionally use the smallest possible weapon for it.

I suppose it doesn't invalidate the discussion, but makes it specific enough that GMs and players should discuss their ideas and expectations for MIUWI's before getting them.

I feel that, as you said, this rule applies to very few players and therefore designating an overabundance of developement time to it isn't worthwhile. One could whip up a chart with locations of mounts, what can be mounted their, if it can be twin-linked or aimed or whatever and regulate exceptions for special armors or compact weapons etc. etc. It's all doable. But maybe it just falls into the area of houserules, instead of main rules.

At this point, I worry that we're just sort of disagreeing about minor details, having lost sight of what the main debate is about. I honestly couldn't tell you.

Of course I can't findthe post about pistol weapons. *shrug*

Maybe you're referring to the RT Errata quoted by Asymptomatic on page 1 (post #8)?

Although it should be noted that it says "likely", understandably referring to the weapon's mass and size as a limitation -- a factor that would depend a lot on the individual gun (not much difference between a boltgun and a bolt pistol) and the individual user (strength and body mass, possibly even wearing powered armour).

If we're being technical, one should also consider recoil .. if it were up to me I'd probably have anything other than a las weapon require a Bracing action to prevent injuries or even being knocked prone. But I suppose we should not force too much realism onto an object that is clearly the result of the Rule of Cool.

As for your pictures (I like them!), I can't tell what kind of weapons those are easily. The second one looks like it could be a handcannon.

Oh, yeah. The first one is Inquisitor Covenant with a psycannon, the second is Ivixia Dannica with a shoulder-mounted gunskull -- fashioned from the bones of her father, by the way. Very 40k.

I'm a bit confused as to what weapon the gunskull is fitted with now, though. Most of the interwebs says autogun, but as I looked up her article on this archived GW website (which also has Covenant's profile ), I noticed it says it's an auto pistol . Given that GW is the original source, I'm inclined to say the various wikis are just wrong and one of the fan editors made a mistake when creating an article which was then copied by the others. Goes to show how important it can be to check the original source rather than rely on the wikis, I guess.

Both figures (and stat profiles) are from GW's own d100 game, Inquisitor, which inspired many of 1st edition Dark Heresy's rules (unfortunately not the wound mechanics, though Inquisitor was certainly not perfect either).

Sidenote: FFG's material classifies the psycannon as a Heavy Weapon, but in Inquisitor it is a Basic Weapon.

I suppose it doesn't invalidate the discussion, but makes it specific enough that GMs and players should discuss their ideas and expectations for MIUWI's before getting them.

Yeah, perhaps that is why the rules were left deliberately vague, as you also suspected. It feels a bit odd for a rather complex system that is trying to over-regulate things elsewhere, but then again DH2 is trying to be more general and freeform elsewhere too when compared to DH1.

I think discussing it with the GM is the best solution here. Tell him/her what you wish to mount and convince them that it should work. The many weapons in this game are so different in bulk, weight and potential recoil (especially as the latter is very much a matter of interpretation too) that it's next to impossible to come up with a proper rule that would not feel weird in a lot of edge cases, and using a huge list of which weapon can go where sounds crazy.

I think discussing it with the GM is the best solution here. Tell him/her what you wish to mount and convince them that it should work. The many weapons in this game are so different in bulk, weight and potential recoil (especially as the latter is very much a matter of interpretation too) that it's next to impossible to come up with a proper rule that would not feel weird in a lot of edge cases, and using a huge list of which weapon can go where sounds crazy.

Agree. Good talk.