I did the same thing that Chris did with respect to the coupler. Inside it is a ply disc (Semroc sells or used to sell them) to form the actual bulkhead between the payload section and the main body.

Based on the brochure (page 2 attached), the motor tube is what projects aft of the fin can.

Attached Files

EnerJet1340 page 2.pdf (1.63 MB, 44 views)

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