A spent a significant amount of time shooting my SR-22 indoors about a year and a half ago. I found that removing the block shifted the POI downwards about an inch a 25 yards, but the groups remained the same overall size. For this reason, I reinstalled the block. It doubt it would make a difference, other than the POI shift, on any other barrel. Simply ensure all connections are tight (and lock-tite if desired). Longer barrels should definitely have the block installed.