Charlotte North Carolina
Examining the engine after recovery, it looks like the propellant burned up thru the center of the propellant mix leaving unburden propellant the sides of the casing. The ejection charge blew thru 1/2 the cap, but deployed the recovery device. The engine seemed under powered for a D engine and made the normally stable model very unstable.
My almost fifty years of model building and flying in this class of rocket I have not had an issue with Estes product ever. This is a first.