I've made them from one piece of brass, bending, swaging it out etc. I used a piece of maple, scooped out, to finish it off. The edges are thinned, and the heel is filled with lead. Works for me. I finish the shaping with a file. I usually start with 1/8th brass sheet, and anneal often. I first saw one on Eric Kettenburg's old web site. He showed a number of photos and the lead filled heel. Since it is forged cold, I thought it would be good practice before trying to hot forge an iron one. I really like the look of a swaged brass buttplate.