Oh my wow... that’s a beauty
I don't know about the M60 FH threading but I would like to hear a review with pictures on the Delta P Adapter.
UPDATE: I saw this posted on AR15 - M60 would be 5/8x24
M249 would be 1/2x28
When I shortened my RPD barrel and bipod to 16" I had an M60 style FH made for it.