CU alloy, BHN and PC

[Phantom30]

Question 2: Although the GC protects the back end from jetting, the front is still mushing along nicely, correct?

Question 4: if the CU jacket protects the core, what effect does a powder coating (PC) have, and at what BHN does Obturation of it kick in for something like HF red coating?

[runfiverun]

take everything you wrote above question-2 and forget about the whole thing.