I made it out of brass so I could easily modify it as necessary. The next i will make out of Stainless tool steel. I have access to a complete machine shop so I can make nearly anything.
A double headed nail, the kind used for temporary assemble would work nicely. Remove the one head and make the nub fit the recess in the barrel, trim to length and using a file and 600 grit paper get it to function correctly. You could heat treat it if you thought that might be necessary. I don't have a picture and have no way of posting it if I did.