The book says the bow has a straight availability of 2, not that it scales by rating. At least by my reading.

EDIT: Someone pointed out that there is a max rating of 6 on new items asides from availability. That counts.

1) so you're saying you think the sample characters are actually made using the rules properly? woah... you must not've looked too close. not that this rules out the bow being legal, it just doesn't mean it *is* legal either.

2) the bow does have variable strength scores to it. ranging from 1 to who knows what. thus, by your definition, it does fall under the rating rule =P

that being said, with availability 2, a crazy superbow of doom isn't all that hard to find in the shadows anyways... likely as soon as the first run ends, you will be able to start looking and find it with ease.

...We had a Troll Adept in our old SR3 group down a chopper with a Ranger X & Dikote arrows. I think his base damage started at something like 18S before staging up.

First, since doubling the velocity requires 4 times the energy (and thus force and work) to span, you're actually using exponential growth there. Second, bows don't work like that: velocity increases start dropping off fast beyond 300fps, and "world's fastest bows" clock around 350fps with very light arrows. I seem to remember someone mentioning a unique bow that managed 400fps with particular arrows, but that's already freaky. Beyond that, just increasing the draw weight will not achieve much. It may well be that achieving velocities over some 500-600fps is more or less impossible with bows as we know them, regardless of the draw weight, even with the lightest arrows. It would be much easier to retain a velocity in the 300-350fps range and just increase the weight of the arrow to somewhere in the 2000-4000 grains range.

This would make for 400-1100 foot-pounds of kinetic energy. The standard M16A2 load (M855) creates 1260 at the muzzle (62 grains at 3025fps).

That's not even touching the problem of diminishing returns from increased arrow weight and velocity. As long as you can fully penetrate the opponent, what determines the size of the wound is the configuration and width of the blades of the arrowhead -- with a 1"-wide 4-bladed head, it makes no difference if the arrow is moving at 250fps or 350fps or weighs 350 or 600 grains when it hits a human.

Umm, no. Not unless it's got a steel shaft and weighs ten times as much as the higher end of the scale I mentioned, ie. about 6 pounds. And it won't, since this isn't Discworld.

First off you'd need the tip to detach from the shaft somehow. The problem there is that the shaft is where a lot of your mass, and therefore kinetic energy, is stored. Maybe if you got the tip to swivel but have the shaft still attached and pushing it. Or had shifted more weight from the shaft to the tip (not sure what this would do to flight dynamics though).

And you'll be fighting the relatively small cross-section to add that extra weight in.

I think that is Nikoli's point, that the upper end's ability to penatrate armor is crazy. Although I really don't think that having AP scale like he suggests is a great idea because it'll top out at AP -5, which is just crazy too.

The idea of something like ((Min STR)/2 + 3)P with a maximum of maybe 7P seems more in order, which leads to just landing single net hit success (basically a peripheral damaging shot) as quite damaging with the target soaking from 8 boxes. So you are dealing with something like a man-portable ballista.

The cross section of a hunting tip is already quite substantial, and those blades are damn sharp. So you are thinking of a linear scoring or something on the shaft so the leading end splits and pokes outward and as it moves foward in he body? That's still is just puncturing, not the cavetation that [tumbling] slug will do with is so damaging because it is an area effect.

I can't get the search tool to find it but months ago I did the math on the range of a troll's bow (with sources) and it turned out to be horrific.

The two factors that contributed most were a) the incredibly long pull length that a troll can provide (bow = spring and increased pull increases total energy) and b) the increased mass of an arrow that has to measures around 60" long (trolls being taller and have disproportionate arm length). The increased mass improves range (inertia resists drag) and ratchets up the KE for the velocity. One could also posit that a trollbow could get away with a head twice as large as normal, increasing the bleed-out from the larger cuts.

Using existing (~year 2000) bow materials, the velocity was around 110m/s (360fps) and the KE was about 726N (534ft-lbs) or what you'd get from a .357 or .44 magnum depending on barrel length. Only the cross-section and drag areas are so much larger for an arrow that 100% of the KE will be delivered by the bow while the bullets will waste a lot with blow-through. Furthermore, the cross-section of the arrow is significantly larger than either round (combining shaft + broadhead) increasing the odds of damaging a vital organ or a major blood vessel.

The cross-section of the broadhead's cutting surfaces is much smaller than a bullet (~1mm square at point of impact vs. .357 ~63mm) so the arrow will shatter/slice body armor like butter. It's like using those gunpowder-powered nail guns; a .22 blank will put a nail into concrete no problem. This is like firing a finish nail with a .357; you can probably embed the arrowhead into an I-beam (though the rest of the arrow will probably shatter when it stops in less than a half-inch). I don't feel like pulling out my steel manuals and checking that out, though.

Why would you want to? At the velocities we're talking about, cutting a wound with a wide broadhead is clearly a more effective way of killing a human.

I'm pretty sure neither would provide any benefit for terminal effect and would cause serious problems with both penetration of rigid objects and flight.

And my point is that it shouldn't be. Any halfway realistic example of a "troll bow" I've seen would be worse for armor penetration than full-powered rifles. If you're capping the damage at 7P, I don't think there's any reason to give it any armor penetration benefit whatsoever. When the weapon really is a siege weapon carried by a troll I could understand a damage code as high as a HMG firing FMJ, but penetration would be probably be worse.

Re: disintegrating shafts, these would probably lead to tumbling arrowheads (which, again, are not a good thing, since you're depending on the cutting edges to cause damage) and very shallow penetration by the shaft fragments (barely breaking through the skin).

The permanent cavitation of even a high-velocity rifle bullet may be quite small -- much smaller in diameter than what you can get with a good broadhead. Deforming and fragmenting high-velocity bullets are a whole different matter, of course, capable of causing a wound cavity over 4" in diameter and still very deep from the average sporting rifle. For example, non-deforming vs. deforming/fragmenting from the same rifle -- note that the former tumbles while the latter doesn't. That kind of effect requires a velocity well above 1000fps, preferably closer to 3000fps.

That's Joules, Newtons are the SI unit of force. Going that low with a .44 Magnum would require a really fricken short barrel.

Err, no. Suggested reading. Also, a massively heavy arrow, even with a very large broadhead, will in fact spend very little kinetic energy in penetrating the human body, since work is only done at the cutting edge. A large broadhead attached to a 300 grain arrow at 200fps will penetrate clear through a human torso and retain some velocity afterwards -- a 3000 grain arrow at 300fps will make a wound that is only larger if the arrowhead is larger, and will retain most of its kinetic energy after penetration.

Or does "blow-through" refer to something other than the classic "over-penetration"?

If you want to make a point about penetrating armor well, you don't want to compare it to a .357. Any common .357 magnum load will be readily defeated by all common forms of flexible body armor right now.

Not that I doubt that a "troll bow" could defeat most current flexible body armors -- but if you're trying to justify an insane damage code like 13P, the arrow needs to be better than a 7.62x51mm AP tungsten carbide AP round, and in fact even better than a .50 BMG SLAP round (which, AFAIK, is rated somewhere around 8P/-6 in SR4). So, how does this 4000 grain arrow launched at 350fps manage against 34mm of rolled homogenous steel armor at 500 meters? Or even 12mm of rolled homogenous steel armor at 200 meters?

That was my intent. Thanks for making it explicit. The only projectile weapon listed in the book with a non-zero AP is the Heavy Crossbow with 7P AP -1 (which I'm not sure why is there, it really doesn't need to be). That's a big part of the reasoning I have for capping bows at 7P.

It really is silly to think of arrows in terms of armor penetration. At least until you make them into something like rigid, solid metal rods (and try accelerating that sucker to high velocity). When an arrow hits something the shaft tends to flex and shake, which actually unchecked can cause problems with penetrating just "soft" targets like big game. A normal arrow at super-sonic velocity, besides having issueds with the flighting, would likely collapse or shatter before penetrating hard armor.

Broadheads (fixed or mechanicals) aren't really about cavities per say, they are about cutting a thin plane through. Which is the core of why tumbling is really conterproductive. They do their damage in a different way.

That's what mechanicals are about. They stay folded in and there is a little lever that when they start going through pulls a forward facing blade out of the tip which then pivots out really wide cutting a serious path. Sort of like you just shot a big ass knife into the target. That area of the cut is what you are looking for, to make sure you cut through as much blood vessle and organ as possible.

When talking about tumbling I had more in my mind the NATO 5.56x45mm fracturing as it tumbles. Also the temporary cavity area is much bigger, but then damage in that region can vary from lots to very little depending what is out there. But yeah, thanks for bringing that into perspective.

Yeah, I was a bit unclear. I just meant that the diameter of the permanent cavity caused by most non-deforming spitzer rifle bullets, even at very high velocities, are smaller in diameter than the width of the wound cut by a large broadhead.

Yup, that can cause wounds similar to the one I linked (i.e. wounds like this). For clarity, the effect that causes the large permanent wound cavity is the fragmentation of the bullet at very high velocity -- if the bullet stays intact when it tumbles, the wound cavity looks more like this, not nearly as bad.

Yup. Liver, intestines or brains get damaged or even destroyed, everything else is only slightly bruised.

I have no personal problem with an arrow doing 13P that might be staged up to 15-16 or so – my only gripe is how it works against vehicles.

Against personal armour they should function as usual, but there is no way that a piece of metal 2 by 2 inches (roughly) and a metal/composite shaft weighting 1/20 of a kilogram would have a chance to go through any kind of thick metal.

Against vehicles I’d count an arrow as a single bullet trying to go through a barrier (DV2) since it lacks the mass and kinetic force (combination of speed and weight in this case) to actually penetrated several inches of steel (in the case of a tank).

The arrow would most probably shatter on impact with the arrow head either ricocheting of the armour or lodging 0,5” into the metal, and the shaft would disintegrate.

Another simple solution is that a projectile weapon without an AP modifier cannot affect vehicles.

The deciline of the armored knight has less to do with the penetrating power of the firearm and more to do with its low cost and its ease of use.

In general, early blackpower firearms don't fare well against the longbow. They have inferior range, inferior accuracy and often have inferior penetrating power comparied to the longbow. Their advantage is that a longbow requires years of training to use with speed and accuracy. A regiment of gunners can be trained in a few weeks. Likewise, a musket cast from metal is more quickly produced than a handmade wooden bow. The gun makes a conscript army far more practical than it would otherswise be. Since armor is expensive and usually only owned by wealthy nobels there is little use for it in a conscripted peasant army.

Of course, modern cartridges fired from modern rifles are far more powerful than and far more accurate than imperfectly formed lead balls fired from blackpowder muskets. A bow shouldn't have more penetrating power than an antimaterials rifle.

Why frustrating?