Abstract: A composite electromagnetic barrel is preloaded to minimize rail separation by jacking the rails radially outwardly away from each other and wedging a pair of insulating members between the rails to retain the preload. The jacking force is then released.

Abstract: A segmented rocket motor case includes wedge members for forcing the case segments into position to remove free play at the joint thereof which may otherwise interfere with or upset the missile's guidance system and throw it off target. A lap joint member for such a joint includes a shoulder having a surface for attachment of a membrane seal assembly for a pulsed rocket motor. A through bulkhead initiator communicates from the forward segment via a fitting which extends through the membrane seal assembly with an igniter for the propellant grain within the aft segment to eliminate the necessity of running explosive transfer lines along the outside of the case from a safe and arm device and other controls at the head end of the rocket motor.