Madcow DX3 XL 75mm MMT with a Aeropack 75-54mm adapter flying an AMW K1130 BB from 26 January 2009. Propellant grains were hard a rock. The motor chuffed for 8 seconds before it came up to full power. RRC2+ reported 7,704' AGL, the AIM XTRA 2.0 reported 7,792'. Nominal burn time is 2.3 seconds, XTRA reported 2.16 seconds of motor thrust. Rocksim put apogee at 9,900 and change; off-nominal flight was due to chuffing and the 808 camera gorilla taped to the airframe.Tilt and GPS data report a very straight flight.