Pictured above is the broken forward assist from my Colt 6933.
I’ve see a few forward assists break. Every time it has come as a surprise to the shooter. Usually what happens is a shot is fired, and the action ends up locked closed, and no one is able to open it using normal clearing techniques. In my case the action locked open after ejecting a shell.
It can be hard to diagnose a jam caused by a broken extractor simply because you can’t see that is what is preventing the bolt carrier from moving.
The best procedure we have found to free up a stuck bolt carrier from a broken forward assist is to:
1. Remove magazine, keep muzzle pointed in a safe direction.
2. Hold rifle with the ejection port down, barrel parallel to the ground.
3. Shake rifle while attempting to move bolt carrier.
Then usually it wont take much to get the action moving again. Immediately clear the chamber and remove the bolt carrier group from the action and remove any loose parts(like the forward assist pawl shown above).
Over the years, I have come to believe that the forward assist should be reserved for emergencies. In practice or on the range if a round does not chamber discard the round or inspect the firearm. I have met many(most former Army) that hit the forward assist after every reload. If your rifle isn’t chambering the round under its own power, there is something wrong with either the rifle or the ammo. Forward assists very rarely fail, but there is no point in slapping it around unless it is an emergency.