Originally Posted by Mosin
did you use duracoat?
DuraCoat loves it some rough polymer as a base.
Pretty much anything Magpul puts out has a rough texture, unlike a lot of other products that have super smooth plastic finishes. It can be a PITA to get adhesion to happen on those types of surfaces. Usually wipe the part down with acetone, let it sit for 15 seconds so it can "chew up" the top layer and create a bite for the finish.