In cleaning up a solder line, I use a hooked scraper. Cuts on the pull stroke, vertical to the surface. Then clean up with emery cloth. In riveting on a rib, I use 6x48 tapped holes about .10 deep. I tap them with a 6x48 tapered tap, then use a bottoming tap, like for scope base screws (available from Brownells). To locate the holes (3 as mentioned above, or 5 like on original Hawkens), I center punch the location on the rib, which is clamped on, and drill through it to just start the hole in the barrel. Then I position the barrel in my drill press vice so when the quill is pulled full down, it just touches the barrel (not the hole). Then I shim up the barrel with a .10 shim underneath. Barrel must be level and square and vice tight. Position a hole under the bit. Turn the drill on and pull the quill down over the hole. Adjust to perfect center by tapping on the table or vise with a plastic mallet. Then when you pull the quill down, the drill cannot cut any deeper than your shim has raised the barrel. Do all the holes.
An easy way to make the screwed in rivets is to use a 6x48 die and cut threads on a nail. A 3 1/2" nail (whatever penny that is) measures about .133 diameter, I think that is the one I use. A duplex nail (double headed) 2 3/4" mikes .137 and one 2 1/2" mikes .130. Cut the threads up about 1/4" and cut the point off square. Cut the "screw rivet" about 3/8" long, with a screw driver slot in the top. You then need to open up the rib hole for the untapped nail to fit through. Then lightly countersink the rib hole, for the rivet to peen into. Screw the "rivets" into the holes, and saw off the rivets so that light peening will fill the countersink. The rivet can be filed to match the rib groove, using a round file. Be sure to peen lightly so you don't bulge into the bore.
You can of course use 6x48 scope base screws, which are expensive, but that ain't the cowboy way. You can even file the (countersunk) heads off so they appear to be rivets.