I get 2" using a benched rifle rest with .530 balls, .015 patches prelubed with wonderlube usinf 70gr GOEX 3F. Mine is a .54 percussion.
I can only do 4" or so freehand.
I know they sure are nice compared to the factory investarm triggers. I do not remember a distinct difference when it comes to the click. From memory cocking the hammer is louder.
They do not market to the same buyer. One is a production percussion rifle and the other a kit to make a flintlock rifle.
There are many on here that have lots of time and are good to fine craftsmen. Others have no time and are all thumbs.