Seems to be some interest in building BC LRs and many of the original BC LRs have the elongated finial on the entry pipe. Here's some pics and explanations of how I make mine. Previously made them in one piece but found the 2 piece easier to make and which are joined w/ hi temp silver solder. I now use soldering paste and have found the low temp solder to be sufficient....either can be used. Both pieces are made from .040 brass sheet that has been annealed by heating to a dull red and either dousing in water or just left to cool which I prefer.
The pipe itself is formed around a 3/8 dia steel rod using the vise jaws but a radiused groove results in the ID when the tabs are formed. I have 1/16 dia hi temp silver solder and lay 2 lengths on the groove which has been coated w/ borax flux. A small parallel clamp squeezes the 2 tabs together. A 1300 degree temp {red color} is req'd to melt the silver solder. When cool, most of the solder is filed off and then a 3/8dia reamer is run through. Because the ID is now round, the tab can be only 1/2" long {don't like such a long slot in the web}.
The outline of the finial is drawn on paper which has been glued to what will become the inside ...notice the 2 square cutouts in the paper....this is to align the centerline of the paper and the centerline on the brass sheet. The finial outline is now cut w/in 1/16" of the layout.
A piece of maple is shaped to simulate the lower forestock and will be used to form the finial....it doesn't have to be the full length.
The sheet w/ the layout is centered on the female form and the forend shaped block is also centered and is then struck w/ a heavy mallet. The final outline of the finial can now be filed.
The end of the finial that accepts the pipe will have to be formed w/ a round tipped punch so the brass conforms to the radiused shape of the form . A drill the dia of the OD of the pipe is clamped as shown and the radiused shape is peened around the drill shank which yields a perfect fit around the pipe. As the peening progresses, that area should be annealed a couple of times to prevent cracking.
The 2 pieces can now be soldered. I stick a 3/8 dia steel rod into the pipe to align the pieces and the rod also acts as a heat sink so the solder in the pipe doesn't melt. A setup for soldering is made and the solder is melted and the BC entry pipe is ready for the filed in grooves and polishing. ...Any questions are welcome....Fred