Hi are there any rules on making a twin linked weapon? And if you were to make a twin linked accurate weapon would the additional hit twin linked provides benefit from the additional dice from the accurate quality?

The closest thing to written Twin-Linked Crafting rules that I know of are hidden in <Rogue Trader - Into the Storm> that only say to smush the weapons' weights together. I could share my opinions on how Twin-Linked weapons could be made, but they would be just opinions.

It's more or less a case-by-case issue for Twin-Linked+Accurate since certain weapons should simply not be Twin-Linked for balance reasons.

Hmmm OK. Well if there are no actual rules I would love to hear your ideas of how to do it. By the flavor text it sounds relatively simple to do and yet yields a decent bonus.

Hmmm OK. Well if there are no actual rules I would love to hear your ideas of how to do it. By the flavor text it sounds relatively simple to do and yet yields a decent bonus.

Mmn... Twin-Linking sounds simple mechanically, but it should be complex narratively. It's not as simple as purchasing an already Twin-Linked weapon since most upstanding citizens wouldn't risk the ire of the Adeptus Mechanicus. Crafting Twin-Linked weapons would breach STCs and might be considered heretical. I'm also convinced that Twin-Linked is too strong as written. +20 to hit? Seriously?

As for my take on adding a Twin-Linked quality to weapons:

• First off, I think doubling a Twin-Linked weapon's weight is too much. A Twin-Linked weapon would have some common features that wouldn't need to be doubled, such as the stock and trigger grip. Making Twin-Linked weapons 50% heavier seems reasonable.
• I'm not quite sure how I would address a Twin-Linked weapon's Clip. For example, breech-loaded weapons' clips are basically limited by their number of barrels. Twin-Linking a musket might double its clip size, but then what happens to, say, a Twin-Linked Las Pistol? Should both barrels draw from the same battery? Again, this is another quirk I would handle on a case-by-case basis.
• Lastly, I want to mention the narrative implications. Brandishing a Twin-Linked weapon among a sea of "normal" weapons is going to turn heads and start some rumors. They're that uncommon. Characters should be prepared to deal with the consequences for having a potentially non-sanctioned weapon.

Twin-Linking a weapon should be a commitment to the setting rather than just for the mechanical benefits. Stagnation and tradition are two staple themes in Dark Heresy that shouldn't be trampled on for personal gain.

Deleted my comment as Asymptomatic basically said it better.

Well to the weight issue, being double might not be so far fetched. While you may remove certain redundant parts, you probably also have to adds parts to link them together. Those parts alone may make up the weight.

I would say that each weapon would retain it's own clip. It Doubles the ammo use, because each one is drawing from it's clip. This would also be why it would Double the Reload time, because you are reloading two clips. (Also in this case another reason why the weight wouldn't drop significantly)

So my third comment and point lol. Perhaps, I'll start writing these all in one in the future. The +20 to hit is entirely reasonable, with extra shots being fired. The more bullets going towards a target, the more likely you are to hit. You only get an extra hit with 2 degrees of success. Which means if you just barely hit because of the +20 you only get one shot on them. If you would have hit without it, you get an extra. If you wouldn't have but are in the +20 range, you get normal.

Written examples of Twin-Linked weapons, such as the ones from {Black Crusade}, do not double the base weapons' weight when Twin-Linked, which is what I am basing my judgement on. More specifically:

• M34 Autocannon at 20 Clip and 40kg -> Reaper Autocannon at 40 Clip and 60kg (+100% Clip and +50% Weight)
• Bolter at 24 Clip and 7kg -> Combi-Bolter at 32 Clip and 12kg (+25% Clip and +70% Weight)

One of the problems making Twin-Linked weapons is that there are so few examples to refer to. Increasing a Twin-Linked weapon's weight by only half may be conservative, but I feel doubling the weapon's weight is too much.

Touching on your clip comment, weapon weight is generally calculated separately at 10% of the weapon's weight; the weapon's clip is not included in the weapon's listed weight but derived afterwards. Simply multiplying a weapon's clip by two has its own problems, as I will address below. I consider the doubled Reload speed to reflect linking a single ammo cartridge to two separate weapons, not necessarily because there are two chambers to reload.

+20 is a very significant bonus at any stage of the game, inflating the difficulty of encounters. Doubling a weapon's Clip means that the doubled ammo consumption is negated for single-shot weapons, putting such weapons on steroids with no drawback. Honestly, I am completely against the Twin-Linked quality as written since it warps the game. At least Storm weapons make characters work for their extra hits rather than handing them free BS. Even then, I would probably knock bonus Storm hits down to x1.5 from x2 to create proper tradeoffs (ammo consumption is still doubled).

Neither of those guns are actually twin-linked versions of the other.

The range is different on the Bolter and Combi-Bolter.

The rate of fire is different on the M34 Autocannon and the Reaper Autocannon.

But if you consider those actual upgrades, then that means rules wise, Twin-Linking only ups the Rarity one level.

Twin-Linking a weapon does not alter either of those weapon stats.

Those are both two examples of unique weapons that have the Twin-Link quality.

"Twin- linked weapons are built this way in order to increase the chances of scoring a hit through the crude expedience of blasting more shots at the target."

Fluff wise, as written, it should get a Bonus to hit.

And also as written it has been this way, rules wise, since Dark Heresy 1.0. They have only changed it once and this was in Black Crusade, and then promptly changed it right back in Only War and kept it in DH 2.0.

Further consider the downsides.

Yes it gives a plus 20 to hit, but if I have an Accurate, Custom Grip, Modified Stock, Sniper Rifle with a Red dot, and I aim in short range, I have a +57 to hit(Single +10, Short+10, Accurate+10, Aim+10, Red Dot+10, Grip +5, Stock +2). That means, the bonus it gives, is only +3 in most common situations, where minuses are not present since there is a max +60 bonus to any roll.

Now consider you use double the ammo. Not a big deal on a single fire weapon. But on any weapon that shoots multiple rounds, you are expending twice the ammo, for one more hit(if you didn't have that +20 bonus, with that bonus, it also allows for 2 more hits in full auto and 1 more in semi auto, keeping it more balanced for the ammo used compared to a single shot.) Autogun shoots full auto of 10. If you twin-link and shoot full auto, you shoot 20 rounds for 1 more hit(If you get 2 degrees. If you don't you have the bonus +20, who would ever use it.

Increased weight is also another downside, probably for balancing reasons. It makes sense as written. It's literally just two guns put together.

"A Twin-linked weapon represents two identical weapons connected together and linked to fire at the same time, often through one pull of the trigger or push of the button."

And not that it's the biggest deal in the world, but on the note of Clip Weight. Clip weight is definitely derived afterwards at 10% of the weapons weight, However, I believe that is so you can know the weight of Additional Clips. I would argue that the weight of a full clip is already included in the weapons listed weight, being 10%. When you purchase a weapon, it comes with a full clip.

"Should it be important to know how much ammunition weighs, consider a weapon's full clip to weigh 10% of the weight of the weapon itself."

I believe we're straying away from the topic at this point. Moving on, the weapons I listed are what I identified to be the closest written examples of what Twin-Linking a weapon would be like, even if the parent and child weapons aren't completely parallel. The next best thing would be using the [Kombi-Shooter] upgrade from {Into the Storm}, which doubles Weight while everything else remains the same, including Clip. However, said upgrade is 1) an Ork upgrade and 2) from a much older book, so I don't consider its ruling reliable.

Keeping in mind that the final bonus cannot exceed 60, the situation you described still has a tentative bonus of +77 that can be brought down by penalties normally. Such a character could harmlessly take up to 17 points of penalties while still holding onto that +60. The fact that the full +20 isn't always applicable isn't a downside, it's just testament to how Twin-Linked inflates BS unnecessarily.

Ammo consumption at higher RoF is ridiculous and balances Twin-Linked thanks to the devils of multiplication, yes. It's the lower RoF I'm concerned with though. An S/-/- weapon gets up to 2 hits for 2 units of ammunition. A -/2/- weapon gets up to 3 hits for 4 ammunition. Numerically speaking, the most efficient ammo expenditures also see the most benefit. Compared to the similar Storm quality that provides no Bonus-to-hit, at least Storm also doubles the number of projectiles Evaded.

Withholding further thoughts on weight since I already shared my view and it'd just boil down to semantics anyway.

Ultimately , I simply disagree with the Twin-Linked quality. I don't care how it's fluffed since +20 is just a big 'no' in my book. There aren't enough levers in place to stop Twin-Linked weapons from being a headache as written. Going by fluff logic, should Storm provide a BS bonus too? No. Quite frankly, I would either defenestrate the Twin-Linked quality or strip it of the +20 while also doubling projectiles Evaded. +20 my foot.