Probably a "must have" - JP Enterprises JPoint 1 Degree Shim Piece

Once the decision is made to go with the JPoint red dot sight I would speculate that one or more of these shims will be needed to obtain the "zero" you are looking for. The sight has a very limited internal elevation adjustment (1 degree) and I needed one shim for my setup with the adapter plate replacing my rear sight. Perhaps a "melt in" installation might have gotten away without a shim. Buy a 5 shim kit along with the sight and you will be ready for just about any arrangement.

I've only had the sight to the range twice and so far I am very satisfied with its performance.