Measure the width of your frizzen at the widest point. With your trade gun at half cock, what is the distance from the jaw screw to the face of the frizzen? Subtract 3/16" from that distance (1/16" from frizzen to edge of the flint and 1/8" for the leather wrap). Hopefully these numbers will be similar.
Who made the Trade Gun? Did they make any recommendations? Who made the lock?
If you know the make and model of the lock, the following vendors will have a suggestion especially based on the above measurements.
Track of the Wolf, October Country, Heritage Products and several other vendors sell black English flints and French Amber. When you order, ask for best quality flints (no humps).
