Welcome to the Forum.
The first thing that you need to know is that the Chapuis is a fine rifle.
Did you have it regulated with the scope?
Pull the front trigger 1st. Hook it with your first knukle. not the tip.
Lee probably makes a crimp die. I use the regular dies myself, if I bother to crimp.
There's good loads available from Graeme Wrights book,"Shooting the British Double Rifle". A must have book.