Steve: making your own nose cap leaves you many more options that trying to make a casting work. To make my Hawken two piece cap, I made a steel former to replicate the tip of the forestock minus 1/16" of wood. I used 1/16" steel sheet, formed the rod groove, and hammered over the tapers on the tip. Then I fitted a second piece of steel to close the front, and silver soldered them together under red heat. Finally, I filed out the steel in the end to accommodate the barrel.
I've been using castings from MBS on Herb's recommendation, but they need quite a bit of work to make them work. They are cast for a 1 1/8" bbl. and for a tapered barrel, they need to be 1 1/16" approx. So they need pinching to close on the barrel, but it's easy to do. then they need to be wire feed welded in the octagonal opening so that I can file fit them to the barrel and have enough steel to match the underrib. If you use a machined solid rib such as those sold by TOW, they're fine as cast, but with a rolled sheet metal one from Rice, or a milled hollow rib from MBS there isn't enough height in the cap from the rod groove to the bottom flat of the barrel. So the welding. The two piece is easier to make and use, but cannot be pack hardened, because of the silver braze.
Roger and Clark: I have no interest in 'expanding' this thread to make it into a PDF booklet. I just wanted to touch on a few of the features of Hawken rifles that might be leaving question marks on some folks minds. Apart from these, much of the building is very much the same as any other muzzle loading firearm. And the way I've presented is simply my way - arguably not the best way either. I'd be pleased to have others present alternative methods - builders such as Dave Rase, Don Stith, Louis Parker, and Herb. A friend of mine is currently building a Hawken for himself. He made a jig that attaches to the barrel to align the deep hole drill for cutting the rod hole without using the rod pipes and rib, as I do it. It's ingenious and works perfectly, and can be adjusted so that the hole parallels the bore rather than the bottom flat. This leaves more wood on the bottom of the lower forestock - a plus.