Brian Thorn wrote:
after that range safety ordered the solids destroyed,
i believe its a zipper like opening on the side.

No, it was blowing the top off, reducing chamber pressure to zero and
therefore ending powered flight.

No. That is an accurate description of thrust termination in a solid
rocket, but that's not what the range safety system in the shuttle SRB's
does; it actually does split the rocket motor along its length and
fragment it into many pieces.

"The Command Destruct System (Fig. 4-1) ... consists of a dual linear-
shaped charge (LSC) running longitudinally along the outboard side of
the cylindrical case from the intersection with the forward dome (XB
531) to the ET attach ring (XB 1491)."

"Upon severing the solid rocket motor (SRM) skin along 70 percent of its
length, the internal pressure created by the burning propellant is
sufficient to open the SRB case and propellant grain in a clamshell-like
fashion. This now weakened SRB structure breaks along seven major
segment joints. The six cylindrical segments of the motor case cut by
the LSC break into twelve pieces, each segment breaking in half at the
clamshell hinge. The forward frustum and skirt and the aft case and
nozzle separate as individual large pieces: The equipment tunnel and its
contents also contribute to fragment production."

From NSWC TR 80-417
SPACE SHUTTLE RANGE SAFETY COMMAND
DESTRUCT SYSTEM ANALYSIS AND VERIFICATION
PHASE III - BREAKUP OF SPACE SHUTTLE CLUSTER VIA RANGE SAFETY COMMAND
DESTRUCT SYSTEM

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA103530