This is the first time I've taken these things apart. The front filler comes apart easily. First drill both rivets/pins on one side to the depth of the flairing on the end of the pin/rivet. Then simply drive out the 2 pins/rivets with punch and then slide pieces apart.
The photos are of a front filler that was lightly touched on the forward edge of bullet ramp and on the left side of the filler. Looks like it is easily rebuildable IMO.
Anyone know of a good source of information on disassembling these receiver parts? As much fun as this is to learn, I'd like to take advantage of someone else's prior experience. It always increases my odds of success.
EDIT ; all receiver pieces come apart with the same method of drilling out the heads of the rivets and driving out rivet with punch and hammer