Would a slingshot be improperly classified as artillery?
A step-by-step solution is:
yes
Artillery refers to ranged weaponry that is predominantly used in breaching fortifications.

Examples of artillery include: howitzers, mortars, and rockets.

Mortars can have a range up to 4,680m.

A slingshot is a string weapon that propels a rock or other small projectile.

Some slingshots can fire projectiles up to 9m.

.

The answer is yes