I'm kind of torn on this one. Firearms can be defined as a weapon or as a piece of machinery designed to expel projectiles at high velocities: Neither are wrong. Machetes are generally classified as agricultural implements but were used during the Rwandan genocide. In the end, words are merely words while actions speak for themselves.
When I think of the first projectile weapon, it was most likely either a rock or a sharpened piece of stick. In that case, would the weapon be the rock/sharp stick, the man throwing it or both? Unlike math which is cold and absolute, words evoke emotions and carry multiple meanings.
Looking at the evolution of warfare and weapons, the human factor is gradually diminishing. A time where man would kill an enemy with his bare hands to a time where man can kill with a press of a switch. Separate the man from the machine, the machine cannot kill on its own* but man can still function independently as a weapon.
I hate to consider objects as weapons since just about any object, no matter how benign, can be weaponized. I also feel that ultimately every man is accountable for his own actions. To even place partial blame on an inanimate object goes against my principles, as the murderer will be 100% responsible in my eyes. At any rate the 2nd Amendment is most definitely not about sporting or hunting, that is a given. In the end I feel there is no wrong or right answer.
*Excluding landmines and traps.
Victim: A hapless individual who waits for third party intervention and/or gambles their life on what little good remains in the heart of their attacker.