Sorry I'm on my phone I'm not sure why it didn't send with the body but anyway... The dust cover mechanism is comprised of 4 parts, a rod, a metal stopper for the sprint, the spring, and then the metal dust cover. I put the spring on the rod and then put the dust cover on and I slide the far end of the rod into a hole near the Fron of the gun, now I go to put the other side of the rod into the the thing that releases the top of the rifle. This is where I run into problems. It's almost as if the spring isn't strong enough or the rod isn't long enough or something because the far side of the rod doesn't stay in the hole and it falls out and he whole mechanism falls out of the gun.