I had a Jukar single shot horse pistol in .45 caliber years ago. (A friend saw it and wanted to hang it on is wall over the fireplace which I felt was a real good place for it.). There is not much to putting them together. You have to fit the lock and trigger assemble like any other kit gun. The ends have to be fitted. Actually it went together very easy. Although the Jukar was made in Spain I do not think it was related to the BPI family of muzzleloaders.

The pistol fired with 15-20 grains of FFFg and a cap. I can not even remember the round ball we shot out of it anymore. It was not accurate. More fun then anything. We'd sit out there after shooting and see who could hit what with it.....

I am not sure if Jukar is even still made. Sorry I could not be of more help.