[metelin]

for an open track i use cutter thats 1/32'' larger, so for an 9/32'' shaft i use 5/16'' cutter. for an enclosed track use a ball cutter to cut profile (a), bill kitto sells ball cutters that are the correct size for the shaft you want to use but they are a bit pricey as an alternative you could use commercially available cutters that will be close to the shaft diameter you want to use and follow the same guide lines as an open track. the track itself could be cut directly into the wood or you could use a polymer like delrin but since this is your first gun don't make things too complicated just cut it into the wood. good luck.

steve