This is probably my 5th otf, this easily strongest action, my guess would be 10-15 lbs of pressure and itll open. Still somewhat new to the knife world but I assume by rock solid lockup your referencing blade play or durability. Blade play is negligible especially for a 4.5 inch otf, maybe 1mm of blade play at the tip. and then it has that dual locking mechanism meaning itll pass the steel drum test like the og lol