That is traditional anti zipper construction. It does work.Stu Barrett, past president of TRA conceived of rear ejection quite a few years ago to help alleviate the zippering problem with "not so accurate" delay grains. This was before there was widespread availability of economical deployment electronics.
I built a 29mm motored project using his design recommendations and by golly it works well.Still fly the rocket too and don't worry so much about the delays. Only thing is the rocket lands nosecone first in a single deploy situation. I've read there have been some dual deploy strategies using his rear ejection concept but never saw one.
Used to be a whole section on the defunct ROL site (Rocketry Online) Kurt
I had an ejection charge failure with a J350 in a LOC tubed 4 inch diameter single deploy. Rocket did the death dive and eventually gravity pushed the loosely fitting parachute down which popped the nosecone off about 100 feet up. The Covert Rocketry parachute "exploded" to shreds, the rocket was zippered of course, got knocked sideways and landed flat. Fincan survived nicely. With the very long 38mm motor stuffer tube I had, I was able to rebuild and decided on a dual deploy as I had a LOC ebay lying around unopened.there must be a simple and effective way of kicking the rocket sideways during main deployment using a drogue system like this; I was thinking about seeing if I could cut a slot in the end of the coupling section so that main ejection gasses kick the rocket over to one side during separation. I am not sure if that would do the trick though.