You will see different replies to you question on the finish for your tradegun. You have several answers to your question stated. "white", "blued" or "browned". It would depend on what the government contract ask for. In many contracts you'll find "white" for all the metal parts (trigger guard, lock, barrel and so on with screws, etc.). Then another contract you'll find "blue" for all the metal parts (trigger guard, lock, barrel and so on with screws, etc.). Usually "browned" was the result of a gun "in-the-white" rusting to a brown color.
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