Now I'm no dwarven physicist, but I can see ways to get a rough guesstimate on the importance of weight. You could take normal-weight iron and see how much you have to nerf its properties before it performs as poorly as light iron. Or you could take a material with crappier properties (like copper or silver) and see how dense you have to make it to get similar results to normal iron.
That is certainly a good empirical way to gather some interesting comparative data. However, I was remarking on the conclusions which could be drawn from the current pool of data, not data yet to be obtained. In any case, first I'd like to identify all parameters which influence ranged damage. I suppose the next one is MAX_EDGE of the ammo used. Does anyone know of any other parameters likely to be used in damage calculations for ranged weapons? Apart from quality, which I believe cannot be changed in the object testing arena (Can it?).
I assume something other than MAX_EDGE is used, because all metals apart from adamantine (100000) have the same value for MAX_EDGE, 10000. (Wood and Bone have 1000). If MAX_EDGE and SOLID_DENSITY are the only two parameters affecting ranged damage, then Heavier is always better as far as metals goes (again, except for adamantine).
Another thing maybe worth investigating is how important bolt density is against creatures of different sizes and skintypes.
There are definitely some interesting ideas to check out in the field of dwarven ballistics. I would assume that larger creatures would take longer/larger amounts of ammunition to kill... but I'm not exactly sure how the damage dealing mechanism works, so I wouldn't know for sure. It's not like larger creatures have more hitpoints, exactly ;] More durable body parts, perhaps? And what are skintypes, exactly?
I would enjoy seeing a report of experimenting with wooden bolts' density since featherwood trees are lighter than even bluemetal by half, and they're relatively poor in performance.
Since the study concluded that lighter ammunition is, in general terms, worse than heavy ammunition, I'd say featherwood bolts performing very poorly is exactly what should be expected.
Wooden bolts of different densities have actually already been initially tested in
Crossbow Ammunition Testing (albeit, admittedly, by way of a non-rigorous testing scheme). The Wooden bolts used by Wrex were, quite by design I am certain, from opposite ends of the wood density spectrum - featherwood with a density of 100 and bloodthorn with a density of 1250. Unsurprisingly (in light of this study) bloodthorn won out. I suspect that the only parameter differentiating wood types is their density, so with woods almost for certain heavier is always better. This would make bloodthorn (1250), glumprong (1200), mangrove (830) and oak (700) the best wood types for wooden ammunition. Most wood types seem to have a density of around 500, the same as bone, interestingly. This would mean that bone ammunition is roughly as good as normal wooden ammo, given their equal MAX_EDGE (Unless you're surrounded by bloodthorn) (Or featherwood) (And unless other parameters which I am unaware of apply).
You could also pick a wood that uses the defaults, and modify its density as done with iron. Make varieties from 250 to 7750, or higher, in 250 unit (or 500 unit if you don't have time/patience for all those tests ) increments to test with. For the lower density tests you may want to equip the firing dwarfs with 150 bolts to ensure definitive results.
Also, running each test more than once, I'd say two or three times each would probably be enough considering its already 100 samples per test, should give a more statistically accurate view of what happens.
All this could be done... however, the cost in time notwithstanding, the cost in dwarfs would be staggering, especially if a high resolution is to be achieved
I lost over a fifteen hundred already just on designing this experiment's setup.
I am sure that many will be happy to hear that no animals were harmed in these experiments. It became apparent that guinea pigs lack certain critical qualities required for operating crossbows and had to be omitted in the final design.