I'm going to attempt to replace the lever spring on my '76. Uberti Customer Service sent me a new replacement spring (no charge, no shipping fee) when I explained to them that the one installed in my new rifle was heavily rusted and pitted. Granted the nasty area was confined to the narrow side of the spring, visible when removing the left side plate. The new replacement spring is perfect and nicely blued, matching the opposing carrier spring. My question is: "Are the two holes on the underside of the receiver threaded or are they simply recessed to accept the screw heads?" I'm asking just in case I have to drill out the screw. I have two replacement hardened screws coming just in case I destroy it and I'd like to replace both of them. So far there is no damage to the screw head though it hasn't broken free. I soaked the screw from the inside and the outside with "Kroil" to no avail. Perhaps an impact wrench could help the situation. I haven't yet struck the screwdriver with a hammer to see if that would help. I have read about "prying" the spring sideways out of the receiver to perhaps relieve some pressure on the screw but I'm not sold on the idea. My inner "Bubba" wants me to use a Dremel cut off wheel from the inside and "Go to Town", but that's a horrible thought. I could just leave well enough alone and have an extra spring and two replacement screws on hand when the rusty spring breaks. I'm venting a bit of my frustration here. Thank you for your helpful responses in advance.