Are you talking about that piece that's on the front of the lug? If so, a Mossberg tech told me not to mess with it as it's pressed in at the factory. Just sayin'.
I started working in a safe easy tool to remove and assemble the gas seal spring and nut. After getting the tool done I was able to remove the spring and put it back together quickly and safely. Without slipping and possibly causing damage. Another advantage is that the tool keeps the spring and the seal properly aligned while reassembly.
I will be making a video in the next couple days to demonstrate how this works.
If I have enough interest in this I will make more for sale. Not sure yet on a price yet.