You are correct; it is a Belgian Colt from the mid-60s! The gun had been stored in an attic and then forgotten. Over the years the original owner died. It was found in the attic, and the gun was offered to me at a great price.
I soaked it in WD40 for an extended period of time. After that I took it apart. More soaking in WD40, and I used a brass scraper (using the case mouth of a flattened 30-06 case) and tooth brush to further clean it. Rinse and repeat. NO ABRASIVE CLEANERS!!!
After that, clean, oil, assemble, and shoot. By the looks of it, the gun had never been fired. The bore and internals were in perfect condition.
It is one of my favorite black powder guns.
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