My personal opinion, and what I intend to do when I get my GP100 44spl, is that it is roughly in line, strength-wise, with the S&W M696. That is, I would not use loads generating pressures above those generated by Pearce's "category 2" loads. Whether the weak link is the forcing cone or the cylinder walls I would rather not find out, and while the GP100 is overbuilt as a .357, it likely is merely sufficient for the 44spl and I see no need to find out its actual limitations.
