Yeah Dutch, I'm familiar with those actions. Actually, I'm a fan of the H&A style underhammer and have one. Their simplicity is a thing of beauty to me, though most people think they are odd, ugly, or both. People don't think of underhammers as "traditional" firearms. But the underhammer percussion gun is a classic American invention dating back to the early 1800's.

There's nothing real practical about what I want to build. I just want to do it, dammit! If it works it will probably be the only striker fired/drum and nipple/adjustable trigger/changable barrel underhammer in the world today.

As far as a safety goes, it won't have one at first. I do have an idea or two for a safety but will deal with that after the gun is built and proven (hopefully) to work OK. Anyway, the face of the striker will not be in contact with the cap when the action is not cocked, so it should be totally safe in the uncocked mode.