1. Do not establish a good stock weld on a collapsible stock as I was trained to do on an M-16. Must keep head Erect like shooting a pistol.
What kind of collapsible stock do you have that doesn't use the exact same recoil spring tube as a standard stock? On every AR or M-16 or M4 I've ever fired you use the exact same cheek weld (nose touching charging handle) whether it has a fixed or collapsible stock.