CTI I303BS (Pro38-4G), dual-deploy (no motor eject). First flight of rocket in "mk VI" configuration, after re-build from previous failure replacing part of airframe with fiberglass (54mm Magna-Frame is no longer produced). Full video from announcement to landing, video stopped on impact with ground though audio recording continued and camera worked fine after power-cycle. Second use of shear pins with this rocket, this time I used two pins instead of one and only one pin sheared when main charge fired. As a result the main parachute failed to deploy and the rocket landed under drogue only, at about 61 ft/s. Minimal damage, an eye-bolt for the avionics bay was bent and a small tear in the avionics bay coupler. 3D-printed Eggfinder sled for nosecone was shattered but electronics survived. StratoLogger CF (SLCF) altimeter flown with data download. Altimeter log (with video correlation): Altitude: SLCF: 3356 ft Top Speed: SLCF: 466 mph Thrust Time: Video: ~1.84 s Coast-Apog: Video: 12.2 s Descent: SLCF: 61.6 ft/s (42 mph) Duration: SLCF: 70.45 s, Video: 69.64 s (video may have stopped before contact) Landed approximately 438 feet from launch pad. OpenRocket simulation suggested: Altitude: 3531 ft Top Speed: 379 mph Max Accel: 13.6 G Apogee @ 14.4 s (12.6 s optimum delay) Descent: 28.5 ft/s (main), 91.3 ft/s (drogue) Duration: 68.8 s