Gunsmithing FSB in Bushy piston ?

[jbgleason]

Does anyone know if the FSB/gas block in the BushMaster piston uppers is the same as in DI uppers? Or is it proprietary to the design?

I have a piston upper, never fired, and I want to convert from the fixed front to a low profile so I can put an extended railed hand guard on it that extends over the gas block.

Thanks in advance.