Here's the gist of what Jani found:

He claimed a combination of best shot pattern at 50 paces and accurate single projectile use, using Sigott's own bullet construction (somewhat like a short Minie bullet with two large grease grooves). Johann Sigott charged 20 crowns (a cost of an imported Iver Johnson 38 cal. break-open revolver) for this magic rifling done on your bad shooting gun.


Kind Regards,

Raimey
rse