Weight vs. Performance.
Could I run an Arisaka M300 body and hyperthrow M300 head and shave 2oz off the front? I sure could. I'd lose my IR capability, though. Could I run an M300V instead of an M600V? Yup. Then I'd get more shadow on the barrel and FS, which is annoying especially under NODS.
Could I run a Ti or CF mag tube? Yup. It would shave some ounces, but it would flex more under firing and accuracy and durability would technically be affected.
Could I run a polymer trigger guard and save an oz over the milspec ones I prefer? Yes, but I prefer aluminum as that is what Aberdeen vetted the gun with. That said, I cannot tell you the polymer is worse and support my statement.
Could I run a RMR or Holosun and not an Aimpoint Micro? I could, but then my light transmission under NODS would suffer.
I've looked at all the things, and thus far, my weapon is as light as can be without making compromises I do not wish to make.