[ithacaartist]

Sounds like the toggle knobs, to me. If you can't draw them up (and back), you can't see into the chamber.

I'd carefully remove the grips and immerse the whole gun in a good penetrant/rust buster before I did anything else in this situation.

Eric, does the barrel extension move in relation to the grip frame? You can check by pushing the muzzle against a stout but padded surface, like an old book, etc. The entire top end of the pistol should move back about 1/4", and the toggle knobs should contact the ramps/ears near them on the top, back of the frame, which, when firing, influence them to begin traveling upward. If the top end is free, it can be removed and its components carefully freed up from the rust bond. This would be part of the process of field-stripping, anyway, to check for serial numbers on the small parts in that system. YouTube has several videos showing how it's done. If the action won't budge, soak it first for a day or three, while you come back for more advice. Don't forget to remove the wood "furniture"!

Can a gun that looks great on the outside be rusted shut? Neglected for decades, you betcha!

BTW, welcome to the forum.