Are the groves and recessions on the FX barrel a necessity? I'm prepping a TJ barrel and didn't know if I could just leave that area at the full diameter? The blank will screw in to a Huma dual transfer port thimble.
From what I've read they are for the grub screw to fit between so liner can't slip by the grub screw but I don't know for sure I have noticed that the grub screw marks are in the center of those so I wouldn't think they are important really