Great rail - Geissele 7in M-LOK Super Modular Rail MK8

I put this on a 300 Blackout that has an adjustable gas block. I was very concerned about clearance, to the point of requesting a cross section drawing from Geissele (which they provided). Based on the drawing it looked tight but there appeared to be clearance. Given Optics Planet return policy, i decided to go ahead and order. There isn't a lot of clearance, but it did clear. The rail is very solid and allows access to the block. The hardest thing about my install was getting the old barrel nut off, from there on its pretty straight forward. I also liked that the included wrench was usable to take the old nut off as well as install the new one.

All in all I am very happy with this rail.