Lightweight Build for Stalk hunts

[StoneTower]

Any way to attach to the 16" Spartan?...(wishful thinking)

That 16" Spartan is really only 14" with the flash suppressor machined as part of the barrel to make it a legal 16". If it is a medium/long range hunting rifle, you are going to need some length to get velocity. If it is a close range blaster hunting rifle, you don't need a high end barrel Grendel barrel and might be better served with something like a Beowulf.