Good tip on the gas block. I assumed the builder of these uppers would have appropriate size holes or blocks. I guess not, just build and get the money.
I found one thread on another forum where the OP made a DIY adjustable gas block by drilling and tapping for 4x40 into a fixed block. There was some discussion of best way to lock it down. Loktite or jam screw or jam nut.
Obviously this is not mil spec, but; I would think some of these mega bucks builders would include this on thier AR uppers or complete guns. I hear this criticism for carbines and (again as a newbie) I am mystified why this problem would exist on any carbine? I mean at least get the sizing close to be optimized, just right, for the 556 . Better yet, adjustable to accommodate any 223/556 loads with just enough.
