I may have misunderstood what you meant by slamming the charging handle forward. To me, it sounded like you were using your hand to quickly push it forward while attempting the chamber a round. Perhaps you meant something else.
The other method you can use is what is called the "Slingshot" method. To use the slingshot method, insert and lock in a loaded magazine. Then, pull the charging handle to the rear and let it fly. Do it right and your hand will snap backward a bit.
The biggest problem slingshoting the charging handle like that is the tendency to let your hand creep forward before the release, or not drawing the charging handle all the way back. Both can lead to the round not being fully chambered.
I hope this clears up any misunderstanding
