I was playing Half-Life 2 and found myself deriving a little bit of sick pleasure by pinning bad guys to walls and billboards with the crossbow. It's such a sadistic little weapon that I couldn't help but think of how it would fit into Black Crusade. The Rebel-pattern Crossbow is a fun little weapon thrown together by insurrectionists on worlds in revolt. It requires an Exotic Weapon Proficiency to use effectively, and can have a scope placed on it. Please, tell me what you think!

Rebel-pattern Crossbow

Basic; 100m; S/-/-; 1d10+5 I; Pen 6; Crippling (4), Tearing, Special*; Clip 1; Rld Full; 5 kg; Extremely Rare

Special Ability: The Rebel-pattern Crossbow fires a single rod at high velocity, burying itself into the target’s flesh. This impact can throw opponents to the floor unless they pass a Very Hard (-30) Toughness test or be thrown back 5m. If this movement leads the target into a solid surface (like a wall) then they are pinned to the wall. They may tear themselves free with a Half action, taking 1d5+5 damage that ignores Armour. If the forced movement does not lead the target into a wall, they are instead knocked prone.

Remember that the original half-life crossbow heated the piece of metal it was loaded with.

1d5+5 sounds a bit too much, maybe reduce it?

PnPgamer said:

Yeah, that was stupid of me. Should be 1d5+2.

I understand what you want to do, but even getting hit with a lascannon doesn't make you prone, or throw you into a wall. Why would a crossbow?

-30 toughness test is too much. Maybe +0.

The ability push might be becouse of the special ammunition that sticks onto the target but keep on their force and "pull" the target with them.

This is Warhammer 40,000. Put little mini-rockets on the bolts that create the push effect.

ShadowRay said:

Why would it? The beam has little to no momentum. It either dissipates when it hits you, or goes through you, but you can't be knocked back either way. A big rod of metal, projected at high speeds, however…

So from a rocket luncher, or a grenade. And it should be harder (impossible?) to move 500kg csm with power armour than 75kg apostate.
Also if something has enough force to do that, the same force+bolt's shape+speed would make it either rip your arm off or go right through it (I know physics doesn't relate to wh40k but it really won't happen).

If you want knockback and so on, add gravitech-mumbo jumbo. Claim that the original idea came from the Lathes or something. There are lots of gravity-manioulating things around.

Re-name it Rebel-pattern Force Bow or something, and we solve a LOT of the problems.

K0balt said:

Lasguns and -pistols have a considerable 'umph' in the WH40k Universe.

Fgdsfg said:

1d10+3 Pen 0 against an average 3 Toughness bonus and 4 AP from Guard Flak. A naked fella could theoretically take a few shots. A guy in armour could take more than a few. That's hardly "oomph."

If I remember right there was a planet during the crusades that had crossbows. However they shot searing beams of energy equivalent to like Bolter.

Manyfist said:

Wookie planet? (Also bolters don't shoot beams. You mean Las?)

PnPgamer said:

It was equivalent of getting hit by a Bolter.

http://wh40k.lexicanum.com/wiki/Interex

They apparently had centaur power armor for better mobility and weapons that looked like bows/crossbows that punched through power armor. They were wiped out, but there's still possibility their technology survived. Seeing how it was Horus that encountered them, and went rogue just a few moments later.

K0balt said:

Both are actually impossible. Any weapon, be it a laser or a solid projectile, that is strong enough to send a target hit by it flying will also always send the person that fired it flying. Recoil is without exception.

DJSunhammer said:

Pretty sure this is wrong. It is obviously possible for a human being to push another human being hard enough that they will go back several meters, without the pusher being knocked over. A well thrown medicine ball can knock somebody backwards with no artificial aids whatsoever. Knocking a person backwards is a question of balance, not of momentum.

And that's even without considering the high-tech options available in the 41st millennium, like self-propelled projectiles.

Chastity said:

So, by your reasoning everyone you shoot, ever, is off balance? Because that is what you are suggesting by saying that a a common bullet or a rod of steel has enough energy to knock a target over. Despite the fact that neither of those have enough energy to knock a person over. Pushing someone over is a matter of mass and leverage, not recoil. The two aren't related.

As for the medicine ball. The physics of tossing something are totally different from the physics of shooting it. To put it another way, exploding something in a confined space to launch another something is not the same as using the leverage of your arms to toss it.

Pretty sure this is true. Now, you could knock someone over with a rocket type projectile, since those gain kinetic energy until they run out of fuel. A very large gun could do it too, but no human could control a weapon that powerful on their own.

The idea is neat though, and it was fun to use in Half-Life.

DJSunhammer said:

It takes *no* energy to knock a person over. It takes energy to *accelerate* a person or to do work against friction, but actually knocking somebody down, or even knocking them backwards, requires very little energy at all.

Running the numbers, a .22LR bullet has a mass of about 2.6g and travels at a velocity of around 330m/s. This gives it a kinetic energy of 0.5*0.0026*330^2 = 141.6J.

That's enough energy to accelerate a 100kg human being to sqrt(2*141.6/100) = 1.68m/s.

Energy is not the issue here.

I'd also point out that the 40K universe *already includes* spear-launching weapons with a knockback - the Scaly Spear Gun from Necromunda knocked its targets back in a straight line.

Chastity said:

The same .22 round that Ronald Reagan was shot with and didn't even realize it until later? Projectiles don't transfer all of their kinetic energy to the target. Much of it is lost in flight to drag and air resistance, and even then, rather than blow someone away, it will simply overpenetrate because bullets impart their energy to a much smaller space than, say, a boxer's punch would. Realistically, if the crossbow bolt were shot with that much force, it would simply tear straight through the target and leave a hole on the other side. If a 7.62mm NATO round (powerful enough to be used in military sniper rifles) can't blow someone off their feet, a puny .22 can't either. People who are shot while standing still aren't blown away, they simply fall over.

To quote someone from the Black Library forums, "Projectile weapons (eg .44 magnum) exert less force than a punch from a ballerina. If you find this astonishing, I suggest you retire to a zen garden with a rubber ball and recite Newton's Third Law of Motion until you attain enlightenment."

Not to mention I find it silly that a crossbow somehow does more damage with greater penetration than a boltgun (with Crippling!). At least the Harpoon Gun is a Heavy weapon, so its damage is somewhat justified by the fact that it (and the projectiles it fires) are zogging huge. It's also single-shot, Primitive (9), takes a long time to reload, and is very short-ranged (40m). You want your Half-Life crossbow? There you go.

The 40k universe also includes human-Eldar hybrids and Kruellagh the Vile, if you want to play that game.

Seriously…

this was a thread of a person wanting to have a fun weapon for himself which would make his participation to the game more enjoyable and memorable, not an argument how it should work in physics.
ditch the logic and concentrate on balancing it.

Where's the fun in that?

Here's the thing about Dark Heresy/Black Crusade. Not all weapons are balanced or equal. In Dark Heresy, for example, for 150 Thrones, you can buy something called a Scrap Cannon, which is Heavy, single-shot, has a 15m range, does 1d10+3 damage, is 3Full to reload, and is Unreliable. For just over a third of the cost of a Scrap Cannon, you can buy a double-barreled Shotgun, which is better than it in every conceivable way; Basic, 1d10+4 damage, two shots before reloading and 2Full to reload them both, and it is not only not Unreliable, but it is Reliable . Hell, for the price of a Scrap Cannon, you could buy a Combat Shotgun, which is even more lethal, and easier to obtain to boot (Scarce instead of Very Rare).

Realistically speaking, the best that OP would be able to get is a Heavy Crossbow from the Inquisitor's Handbook. Forget about nailing people to walls, unless they are standing right next to a wooden wall already. And it certainly won't be blowing anyone away anytime soon, especially not a 900 pound Grey Knight in Terminator armor. Maybe if you equipped it with barbed arrows you could give it Crippling, which is pretty much as close as you'll get, but it still won't be particularly good at penetrating armor.

I didn't like the Half-Life crossbow anyway, I rarely ever used it. I preferred the Magnum or the Pulse Rifle, and for a "fun" weapon, the Gravity Gun beat it easily.

How about giving it Accurate and reduce the damage too 1d10+2 R, Pen 3