The S&W 3000 is essentially a copy of the Remington 870. The bolt should stay locked when the gun is fired until the action is released by a slight forward movement (just a mere fraction of an inch is sufficient) of the forearm. Recoil from the fired shell is usually sufficient to supply this amount of movement to the forearm. Especially with heavy loads, this can give the impression that the action is blowing open.
Take the gun to a place where it would be safe to fire it. Check the chamber and magazine visually and by touch to make double sure the gun is empty. With the muzzle pointed in a safe direction, pull back firmly on the forearm, push off the safety and squeeze the trigger. The action of the empty gun should stay locked until you intentionally move the forearm forward a fraction of an inch to release the action lock.
Mindset - Skillset - Toolset. In that order!
Attitude and skill will get you through times of no gear, better than gear will get you through times of no attitude and no skill.