M16 Barreling Spud
This tool is designed to be clamped into a vise for use. The parts of this tool are machined from 4140 steel and nitride finished before assembly. The spline end is machined to engage the barrel extension and the screwed on key is lined up with the gas key / charging handle channel in the upper. These 2 features together keep the upper properly lined up to barrel during assembly / disassembly of the barrel nut and muzzle device.