My Cheekpiece on the ACC has to be lifted slightly to close as it hits the bolt knob on the Impact 737. To make it easier on me to have repeatability, I added a stop collar and a 5/16ID O ring. Puts it right where I need it. I forgot the size as it's metric, ACE didn't have SAE in black. (3/8" SAE) I could have done without the O ring, but I had them.
Thought it might be helpful to post it. In the past I used a stack of rings on the MPA I had.

Thought it might be helpful to post it. In the past I used a stack of rings on the MPA I had.
