1/4 Mile Potato Gun Cannon - The Eliminator Barrel Length: 48" Diameter: 1.5" | Chamber Length: 24" Diameter: 4" | Overall Dimensions: 77" x 5" Manufacturer provides excellent customer service and technical support at quartermilecannons.com MANUFACTURER RECOMMENDATIONS: Watch QMC video on assembly & troubleshooting. Use only aerosol hairspray. Try from 8 to 12 seconds of spray depending upon altitude. Trial & error is necessary to obtain maximum distance. Customer feedback & videos vary drastically based on whether assembly & firing instructions are followed precisely.