Just about any weapon is used in war, especially in our recent occupied areas, so that is a vague description if I ever heard one.
I sometimes carried a slingshot on night ambushes in Vietnam.
Why? If we heard movement, our choices were 1) ignore, 2) toss a grenade or 3) open fire.
2 or 3 would give away our position. A slingshot would also make a "thwack" sound, but not nearly so loud. I figured that if the movement was NVA/VC and my aim was good, it would produce a stream of Vietnamese profanity.
(BTW, I never had opportunity to test my theory)
Because the slingshot is a 'weapon of war', it HAS been outlawed in Massachusetts!