My first 4 LRs had staples made from nails and after forming , each leg had at the end of the leg. a groove filed in. I bought TOW's double center punch but used it only once...preferred a single one. The tricky part is drilling the holes....first drilling w/ an angled drill to pick up the center punch and then a flat bottom drill to get maximum depth. The staple is pressed into the holes and the metal surrounding each leg is peened into the grooves and the entire area filed smooth. When drilling, used the drill press spindle stop plus a stop collar on the drill.
After the 4th LR, switched to dovetailed bbl lugs.....too much "fiddling" around w/ staples VS filing a dovetailed slot.....Fred