I can not understand it Rich, my triggers are light, V light on some and never had a problem with no fly. Must say I am at a loss as to why.
On English locks, I suppose some flys were fitted on rifles, but I never saw any. As for fowling pieces, I never saw a fly yet, Not ever.
I am still wondering about this, and can not come up with any sensible or logical conclusions. (Furrowed brow and all that....)
I did hear Decades ago, that if a lock is made right, it does not need a fly; I state this for what it is worth, and for no other reason.
I would like to ask Mr. Jim C about this.