This is not a full tutorial. Just an explanation of how I have done it and still do on occasion. Very often I see questions about where to buy items that can be easily made by the indidual. Making your own things is fun and satisfying. And, usually, much less cost than buying commerical items.
As for jags, they do not need to be made of brass. Wood and antler will work just fine and last a long time. Not forever, but a long time.
Long before I had a genuine workshop I made and modified jags for my own use. I didn't have a lathe. I had two 'sorta' drill presses. One was an antique hand crank and I used it often for quite a few years. The other was one of those affairs where you clamp in a corded electric hand drill and used like a drill press. That was my 'lathe'. I didn't have any proper lathe or machining tools. Didn't need them. I bought old files from flea markets or wherever. For cutting edges I simply broke a file (be careful and wear protective eyewear for the breaking part) and that was my 'tool'. To get a grip in the chuck I would first file or cut down my material with hacksaws or the file until I had a shaft. When I had that I would chuck the piece and turn on the power. Without a tool rest I would just hold the side of the file against the item until it was round. Then I would switch to a sharp edge and form the piece into something that looked like a jag. Using the barrel I would check size until it was right. Sometimes I had to put back onto the 'lathe' to get the grooves right so they would hold the patch. With practice it was easy after the first attempt. Then removing from the chuck the shaft could be threaded with a die or permanently glued onto the end of the ramrod. Keep in mind, 'back then', 'they' didn't have lathes and tools in the woods other than knives and such. Ramrods (wiping sticks) had to be made where they were with what they had. It is satisfying to make your own and really not all that difficult.
BTW, an antler tip rod really looks nice.
As for jags, they do not need to be made of brass. Wood and antler will work just fine and last a long time. Not forever, but a long time.
Long before I had a genuine workshop I made and modified jags for my own use. I didn't have a lathe. I had two 'sorta' drill presses. One was an antique hand crank and I used it often for quite a few years. The other was one of those affairs where you clamp in a corded electric hand drill and used like a drill press. That was my 'lathe'. I didn't have any proper lathe or machining tools. Didn't need them. I bought old files from flea markets or wherever. For cutting edges I simply broke a file (be careful and wear protective eyewear for the breaking part) and that was my 'tool'. To get a grip in the chuck I would first file or cut down my material with hacksaws or the file until I had a shaft. When I had that I would chuck the piece and turn on the power. Without a tool rest I would just hold the side of the file against the item until it was round. Then I would switch to a sharp edge and form the piece into something that looked like a jag. Using the barrel I would check size until it was right. Sometimes I had to put back onto the 'lathe' to get the grooves right so they would hold the patch. With practice it was easy after the first attempt. Then removing from the chuck the shaft could be threaded with a die or permanently glued onto the end of the ramrod. Keep in mind, 'back then', 'they' didn't have lathes and tools in the woods other than knives and such. Ramrods (wiping sticks) had to be made where they were with what they had. It is satisfying to make your own and really not all that difficult.
BTW, an antler tip rod really looks nice.