Some guns aren't worth the money it takes to repair them the right way. A soldered shim will likely last the life of the shooter who installs it, which, is "right enough" on an old, shooter use gun. Feeler gauge is ground and hardened, and regular shim stock might be a better choice. There was a story about Nitro Lefevers in the DGJ a few issues ago, and how the guy had used one with pretty heavy loads with a brass shim that wasn't soldered for several decades. Thats a good, low buck repair.
Best,
Ted
