I recently used a similar method to remove a stuck case and wanted to disassemble my firing pin for learning purposes and this was the first thing to come to mind. If you have to swap springs in a pinch and don't have a tool hopefully this helps you out. You'll need a reloading press, a 1/4" fender washer, a 1/2" fender washer and a 1/2-13 nut. Put the 1/4" washer on your shell plate. Drop the fp in. Put the 1/2" washer on from the bottom then screw on the nut. Lower the handle and tap that pin out!
