I actually like my Archangel Opfor stock, but I rcognize it needs a couple of tools for takedown.
First is a pair of slipjoint or channel lock pliers. They make that insert very easy to squeeze and pull out.
Second, a large screwdriver or ice pick against the pistol grip to pop the trigger group release.
Just remember to charge the action with the safety on beforehand, and it's really easy.
After the mag drops away (if you were using the fixed mag - AR adapters and duckbills don't have to wait this long), off comes the stock.
Finally, break down the topside per usual. Assembly is reverse...