Thanks for the write-up David. I had all but given up.
I have the M&P BG 380. I am an M&P Armorer and have changed triggers on all my other M&P's, so was comfortable doing the Galloway mods and XS sights.
When I bought it the FTF was about 1 in 6 (Never a full mag without FTF), I wasn't too concerned since I was doing the Galloway short stroke trigger and tool steel firing pin. 100 rnds later and Galloway kit, better, but still FTF - I was surprised. I had to run through the state qual course with it and just double-actioned the FTF to get through the course.
Called Galloway and they blamed the ammo (so much for 100% satisfaction). So I ran a test of 12 ammos with OEM and Galloway kit (PITA) to show it wasn't the ammo - which got me to the right conclusion {pssst, it's the pistol stupid}.
Although it was a very bad customer experience with Galloway, they did point me to the root of the problem. I ordered more springs from Galloway to see if that would make a difference, it didn't. Next I tried removing the firing pin blocker thinking this was preventing the firing pin - without blocker no change in operation or FTF.
Damn, just one more step, you have discovered it is the other indentation, on the firing pin retaining pin, not the blocker.
Thank you, thank you, thank you. This is by far the most accurate and comfortable of the 380's and now I can get it up and functioning.
Since I have both OEM and Galloway firing pin I can experiment now, the only drawback is that it is a serious PITA to remove the firing pin, mod, re-install, test, remove, repeat.
With your pic I'm going for once and done mod. Will see if I can mod the firing pin as your picture indicates and get it reliable.