I machined a new firing pin the correct size for Musket caps.
Adapted a spring for the new firing pin.
Removed the action bushing for the firing pin and bored it to match the new firing pin.
Installed a 51# hammer spring.
Drilled and tapped the breech plug to accept a Musket nipple.
Drilled and tapped a hole in the top of the breech end of the ML barrel.(exposed to the elements)
All these changes can be brought back to original condition by replacing the modified parts with original equipment part. The hole in the barrel can be dealt with, with a threaded plug.
I took it out and shot it. It works. It is an Encore ML that is legal for Idaho.