Steel shim material is available from Brownells,I bought the package and have enough for several life-times. If you are doing one gun and need shim stock email your address and thickness needed, I will send you enough for 3 or 4 tries. Hint; measure play with a feeler gauge and deduct a little for the glue or solder.

Jim

I learn something every day, and a lot of times it's that what I learned the day before was wrong