Two part gas blocks are not needed in the majority of instances, they are more complicated and a little more expensive than the standard gas blocks.
However, sometimes they serve a purpose. Today I need to install a YHM Spectre Two Piece AR-15 Gas Block because I plan on permanently attaching a large flash hider to a barrel and I will not be able to slide the gas block off if I ever need to change barrels.
By welding on a flash suppressor the gas block cannot slide off, this means i cannot change or repair my gas system.
This is really the only reason I can see for a block like this.
It needs an Allen key and roll pins to install. You also need a vise and a vise block to support the upper as the gas tube is pinned into the gas block.
The only difference between installing this two piece AR-15 gas block and a regular one piece gas block is that it does not slide on, it fits over the barrel and the four Allen keys are tightened to clamp the block to the barrel.
When tightening the Allen keys be sure to tighten them like you would with a tire. Alternate the bolts and don’t got 1,2,3,4.
