This is, without a doubt, the worst part of re-assembly. Just like many people, that light snapping motion of the Brownell's videos is not how it actually works in all my cases (I have multiple SKSes of varying years and they all have the same issue). In almost all cases, I have one of my kids hold the stock stable while I use both hands and lean all my weight into that trigger group with a QUICK, SHARP downward angled movement. The key is the quick, sharp movement, not a gradual push down (which never seems to work).