[John Sabato]

I think I see an option that has been overlooked...

First use Ron's procedure to remove the recoil spring and take the tension off of the upper receiver and toggle...

The upper receiver has no barrel currently installed.

I would turn and thread the stub of a large cyliner of steel (say 1.5 to 2" in diameter) to properly fit the barrel threads in the reciever to a "hand tight" condition.

The diameter of the cylinder should be large enough to provide a perpendicular "pounding" surface while the gun frame is held in a vise padded with some thick leather or hardwood.

This should allow you a place to exert the impulse force necessary to overcome the pinch of the dented frame without striking any portion of the gun parts.

I would use either a block of hardwood or brass as the impulse device being driven by at least a one pound sledge hammer...

With care and repeated blows, this procedure should enable you to get the parts apart without damage.

Where are you located, perhaps a member of the forum is close to you to give you a hands-on evaluation or help?

Once the parts are separate, you can judiciously file or stone the pinched areas to permit easy movement.