The Gunsmither™10/22® Barrel Block is made to replace the wedge shaped 10/22® factory barrel locking block, which tends to pull the barrel downward, due to loose fitting factory barrel shank/receiver tolerances. It will also work with loose fitting aftermarket barrels.
Many 10/22's have sloppy fitting barrel shank to receiver hole dimensions. This loose condition allows the factory wedge type barrel block to pull the barrel slightly downward, causing the infamous, so called "Barrel Droop”, or “Sag" condition.
I have found more than a few 10/22's where the wedge block was pulling the barrel down, and the stock forend pressure was pushing the barrel back up! The barrel is actually bent into a curve when like this. Shoots fine with open sights. However, when the forend pressure is relieved by free floating the barrel, the barrel "Droops" downward, causing low shooting with a scope. Many scopes do not have enough elevation adjustment to overcome the low shooting condition caused by "Barrel Droop".
The Gunsmither™ 10/22® Barrel Block allows the user to put slight upward pressure on the loose barrel, doing away with the factory barrel "Droop". This allows greater scope elevation adjustment without using unsightly scope mount shims. Installing this block requires a slight modification to your gun barrel that will not affect re -use of the factory block should you desire to do so. A simple 2 minute job with a file is all it takes to create a flat spot for the Gunsmither™ block to push against.  Very easy to do!