Most standard slingshots(standard wristrocket type with yellow band) shoot well under 280. We used them at a youth camp, fun for while. Especially watching one of the girl counselors chase one of the guys all the way across the field. She stayed within about 8ft and never actually shot him, even though we were yelling at her to do so. When she finally took the shot and missed we all about died laughing. ah good times.
Most kids have never shot one these days, so I tried doing a forward rush to get a better position and wouldn't you know it I got hit 3x times in the chest by the little buggers. oh well