Hortonstn,
This is a re-post of part of the work I am doing on the muzzle cap for the tiny rifle I am doing for my grandson. Thought it might be of some help......
First step, cut out a piece of 0.032" thick brass sheet and anneal
Second, do an initial form around a piece of EMT tubing
Next, refine the curvature as the cap rolls in to contact the barrel sides. This is done with a nylon hammer and a steel mandrel.....
The lips of the cap were left intentionally a little long, so here they are trimmed to proper height
The height is checked on the barrel (upside down from where it will be installed, but a good place to check at this stage in the fabrication process)
After cutting a small piece of brass for the front of the cap, both pieces are cleaned of oxide and surface dirt, fluxed, and set up for silver brazing
Here I have cut a couple of small pieces of silver braze alloy and will melt them into a ball and pick them up while still molten on my soldering point
The parts are heated to brazing temperature from the outside and then I have placed the solder on the inside of the joint. It runs immediately and the second piece of solder insures that the entire joint is complete.
After brazing, a quick pickle in dilute hydrochloric acid to remove scale and flux residue
A quick inspection of the joint shows it to be tight and completely brazed
Most of the excess brass on the face piece is clipped of with tin snips
A few file strokes and the face piece is brought to near final contour
Now I smoked the end of the barrel and put the cap in place so I can tap on the face piece with the nylon hammer
The result is a smoke print of the muzzle on the inside of the cap. The barrel flats are beveled slightly at the muzzle so the print is a little undersized but it will allow me to get very close before the final fitting.
Most of the face piece brass is cut away with files and some back and forth check to get a tight final fit
Final check on fit and the completed tiny cap
