To begin with, you have to make sure you have a Darne-if it doesn't say Darne, it isn't a Darne, and these instructions likely won't work.
Further, these instructions are particular to an R model, which, if one has a Darne, it is most likely to be.
After one has removed the breech, one will see a piece of round metal with a flat spot milled on the front(flat spot toward the barrels). When you removed the screw closest to the triggers, in front of the tang screw, it was threaded into this semi-round piece. You can usually use a very fine pin punch to drive this out from the bottom, being careful not to mung the internal threads. Sometimes, oil from the action will have turned to varnish and make this a tough job. A drop of Kroil will definitely help things along.
The screw that retains the stock is hidden behind this piece of metal. I've had about a 50-50 chance of getting the screw out without removing the forked main spring when I take a Darne down. If you can't get a solid bite on the head of the screw, (barrels off, of course) remove the forend wood and drift the pin that holds the main spring out. You will notice the pin has a slight bend, don't be tempted to straighten the bend out, it is needed to create some drag on the main spring, to keep it from flopping around in the gun.
An aside-DO NOT be tempted to use tools of any sort to move the main spring up or down for barrel removal-this is asking for a broken Darne-the tip of one's finger, or the tip of a plastic ball point pen are both more than enough for the job. Break one of those serrated forks off, and you have an expensive problem. Always push on both forks, not just one, to unseat the barrels.
Good luck. More than one very good gunsmith has been otherwise completely stymied by a Darne.
Best,
Ted
