Home Depot and Lowe's usually don't have them unless you buy the whole set.I went to home depot and I couldn't find them. I guess they are marked different and I don't know.
I use copper washed mild steel welding rod for pins. The size I use is .095, it’s copper plated so it doesn't rust. Get your caliper out and pick a drill close to it and proceed (with the lug slotted for clearance). It helps to tape the stock on the off side to reduce chance of splinters and when you tap the pin thru it helps to chamfer the front end.Dad.........Long rifles w/full length forearms need at least three barrel pins to be functional. One between the entrance r/r thimble and breach , and two between the entrance thimble and muzzle. If you have a micrometer , measure any wire between 1/16 th " about .068 " , to about .070". The hole's in the barrel lugs should be elongated and sloppy anyway so the barrel can work when fired,and to allow for expansion and contraction from temp. changes. Muzzleloaders are not precision instruments by today's standards. By !8th century standards , today's m/l's are more precisely made ,than the old masters could imagine because we have better tooling. One simple but effective source of spring wire barrel lug pins ,are those small marker flags farmers , and other folks that use marker flags. They can be found most anywhere from hardware stores to Lowes , farm stores , etc.. .......Since a 1/16" drill bit measures .068" , and the flag wire is .070" , cut an ample 2" long section of of .070 wire and chuck it into your hand electric drill motor , and reduce the wire size to !/16 " using emory cloth and running the wire between thumb and for finger. Only 1/2 the pc. of pin wire needs reduced to fit the 1.16" hole in the stock wood. Hope this dissertation helps...................oldwood