Okay, here it is... Gas block: clamp style or pinned Noveske Switchblock: is it worth it or not? I will be running suppressed and unsuppressed. Barrel and gas port erosion: is it more prevalent while using a sbr? SBR and carbon fouling: is it more predominant, carbon build up, using a sbr as opposed to a standard length barrel? Which would go back to using the switch block from noveske. Buffer spring assembly: do I need to be using a different style or weight while using a sbr and suppressor? In regards to the sbr...it is going to be a MK18 built on a colt LE6920. I will be using the M4-2000 AAC suppressor I appreciate any and all the help and advice you all have!