Used Estes C6-3; and it rose up beautifully.  Arced over a bit and after apogee t' charge blew t' rocket apart. Arrr!  I had made sure with a poke test that t' parachute wasn't too tight, but t' charge made t' rocket come down in 5 pieces (nose, matey, parachute, me bucko, body, motor, motor retainin' ring).  I think it be a certain lot o' C6s I had (from Estes Blast Off Flight Pack) with too much ejection charge.  Broke a body fin on landing, but will fly again...maybe after some modifications.