It depends on what you are comfortable with. I like fixed stocks because they feel more solid to me. I have tried even the locking adjustable stocks but like the fixed stock better. Also allows you to run a rifle length buffer. This set up with adjustable gas block on mid length 16" is a very smooth shooter. I have a fixed stocked (PRS) on my 20" 223 wylde also with adjustable gas and rifle length gas system which is also very smooth. The only adjustable stock I still have is waiting for when my form 1 gets approved for my 9" blk.What do most of you prefer an adjustable stock or a fixed stock. The current build had a 20" barrel.