In my experience, the sear spring on Pedersoli bess locks is a little too short. The end of the sear spring should just clear the bolster on the sear.
I made a new sear spring for my bess, 'cause I wasn't satisfied with the old one. IMHO, making a new sear spring is almost child's play compared to making mainsprings, so IMHO, anyone can make a replacement with just a little work.
God bless