I have a race of carnivorous mammals living in a very resource-poor environment. Due to a mixture of lack of resources (no metal, no wood or tough stems, etc) and cultural taboos, they are only allowed to build weapons out of materials taken from living animals that they have killed (finding a long-dead corpse or using coal or oil taken from long-dead creatures would not be valid). Plants could technically be allowed, but only algae-like slime and lichen are available.
They have access to tough fabrics such as leather and plenty of bones, along with any other part of the animal that might be useful (tendons and so forth). Stone may be used in small amounts, but the "frame" of the weapon, along with any damage-inflicting parts (blades or projectiles) must be biological in origin. Gunpowder-like explosives and oxidizers can be derived from the rocks and may be used in small quantities.
My race preys upon very small (rat-sized) and very large (elephant-sized) animals, so bones can be made arbitrarily large or small. Their physical strength is comparable to very well-conditioned humans.
How advanced or effective of a weapon could be created under these circumstances? I'm primarily interested in the possibility of shotgun or pistol-like projectile weapons, but I'd also be interested to learn about what kind of restrictions might be placed on melee weapons. Bonus points for hypothesizing the construction of heavy artillery, flamethrowers (possibly powered by animal fat?), rocket-launchers, or other interesting weapons.
I'm most interested in weapons of war. This race tends to settle personal conflicts with their own claws and teeth. If it makes a difference, these weapons are intended for use against humans with WW1-era armaments.
EDIT:
Specific issues I'm thinking of:
- Weapon lifetime (effects of use of weapon condition).
- I'm guessing needle-like bone splinters would be the most effective ammunition. Is this true? (I'm thinking about density and muzzle velocity but I don't know any numbers).
- Aerodynamics, range, and penetrating/stopping power of projectiles (most likely bone).
- Ammunition details: are clip-based reloads or full-auto triggers possible? (I doubt it).
- Structural strength of weapon: could a bone shotgun be used to bludgeon, or would this severely damage the weapon?