Anything that propels a projectile toward someone or somethin and is designed to do so is a weapon.
A fork is designed to be used to eat food. A sling shot has a similar shape but is designed to propel a projectile. It's a weapon. That's its design.
Sharpshooting/competitive guns can still hurt a person (a blank can hurt a person). Their design is to propel an object at high speed toward a target. It's a weapon. Blunderbusses and muzzle loaders are inefficient by modern standards, but have killed thousands and thousands of people in past centuries. That's what they were and are designed to do (send a potentially lethal projectile toward a target).
That's why in gun competitions, everyone follows all the rules of gun safety - although Lord knows that mishaps still result in human injury and death.
We report three cases where fatal neck injuries were caused by blanks from starting pistols. The weapons were loaded with blank cartridges or tear gas cartridges. Neither live ammunition nor any form of projectile was used. All three cases involved a contact discharge. The gas pressure caused by...
pubmed.ncbi.nlm.nih.gov
Competition rifles are usually semi-automatic and fire .22 or .223 or similar caliber. My policeman friend told me to get a .22 pistol for home defense - and my dad used a .22 revolver for home protection. Competition rifles are quite sufficient to kill a person with; so is a .22
In fact, I regard a .22 (including airsoft that has a similar size) as excellent weapons for several purposes, including anti-personnel if that's what the task is. I sure hope I never have to use any of these guns for that purpose.
You can do some eye damage with a pea shooter. Even more with a sling shot. And you can kill someone with any .22 ammo, if you know how to shoot. IMO. The rifle recently posted above uses .22 LR - exactly what I have in my pistol. It is deadly at both close range and long range. No point in giving more pointers, but no one should think that those competition rim fire .22's are toys - they are weapons, they are lethal, and are treated as such by any sane person who wields one.
IMO.