Looking at the Pedérsoli "howdah", one reason for that butt ugly ridiculous pistol stock might be it was required to reach the front trigger? As pointed out in the "What is a howdah?" thread, a real howdah pistol has curves near the trigger, tang etc. A shotgun action is more straight. Why existing shotgun actions might not make good howdah conversions? A reason for that aweful pistol grip.

Pity as one of these would make a nice howdah shooting competition handgun. Relatively cheap. I would still try to restock one with some sort of "banana" extreme curve perhaps? Might even handle worse than that US car grip?

As for shotgun conversions I'm sure some .410s with hammers might be better? Maybe other gauges?

I do strongly prefer hammers on a howdah.