If anyone is interested in a clean and inexpensive parachute ejection system, check out this little gizmo I made. It uses a small black powder charge to open the CO2 cartridge, and (most of) the BP gas is vented out the side of the rocket, keeping everything inside clean and free from burning or melting. I tested it on an 11.5" x 10" chute compartment and it worked perfectly. Next I'll test it with shear pins but I'm not ready to drill the holes just yet. All parts were from a hardware store and Home Depot and it costs about $15 to make. It weights 4oz, 6oz with a 16gr cartridge, so it could be used on smaller rockets too.