This thread on TRF raises some possible issues with the new Blue Tube. Basically, when unreinforced, it can temporarily bend under high-heat, high-humidity conditions.
The bending is apparently because of their original use: a liner for large artillery shells. It needed to bend to conform to the shell as it experienced aerodynamic heating.
On the thread, Randy, the owner of Always Ready Rocketry, who is the primary dealer for Blue Tube responds. Yes, at Southern Thunder, under extreme conditons, 3" and 4" rockets, which were 8 feet long, bent somewhat in area without internal components. The bends were temporary and the rocket flexed back into shape in cooler, drier conditions. It took them a while to bend, and that was under extreme Florida conditions.
Randy also mentions that they're working on adding a binder to Blue Tube that won't bend in the sun. He says that once that is complete, it'll be the "holy grail of airframes".
In short, it's a minor problem that affects few that'll get better. I still plan to use 29mm Blue Tube for the eventual sucessor to the Machnum Force.
The Boston Projection
17 hours ago