Airburst MegaBoom Supersonic Target System (STS), Pressure Gauge
Airburst MegaBoom Supersonic Target System (STS) Includes oil-filled air pressure gauge Attach plastic soda or water bottles for some shootin' fun! Shooter and all other people in the area should be at least 15 feet from the STS when the bottle is shot Directions included Up to 150 decibels of boom! According to the manufacturer, lightweight pellets will penetrate the bottles and exhaust all the air but will not cause a supersonic boom (the bottle doesn't blow up). In .22 caliber, they told us that the lightest pellet that blows up the bottle and causes a boom weighs 14.3 grains. They have not provided a minimum-weight projectile for any other caliber. However, the manufacturer states that slingshot ammo will blow up the bottle (and cause a boom), which suggests that the weight of the projectile is more important than speed.