Disassembled, cleaned the firing pin hole. Had a little dirt, not much. Also cut two coils off the firing pin spring, reducing its length from 30mm to 29mm, a 3% reduction (photo only shows 1 coil, but I ended up taking 2 off).
As originally made, the pin works merely by inertia; it's too short to make direct contact from the hammer to the primer. Photo doesn't show this, as the back plate that secures the pin adds distance.
I'm traveling this week, when I return I'll test it and let you know if this gives better primer hits.
Bear, Anni, and BBob, I think the Spfld 911 was a copy of the Sig P238. I've heard some parts interchange. Main difference is 911 has an alum alloy frame, and P238 is steel. I chose 911 for that reason, to go as light as possible.