For a 3/8" dowel, you can make the tips with .38 Special or .357 Mag cartridge cases. Knock out the primer. Drill and tap the flash hole for 10-32 threads. Turn down the rim of the case head by putting the case in a power drill and using a file or sandpaper on a wood block. and fit it to the end of the dowel. You can pin it if you want, but I use a little epoxy to hold it and it works fine.