My L1 rocket is a "traditional" DD rocket, and I have been blowing the nose for the main. However, as I've gotten better at packing chutes the main inflates more quickly, and now it is prone to zippering...the last of which was 4" long. Since I needed to make a new payload tube I reversed the screws and the shear pins, so it will separate at the electronics bay (midpoint) in the future.