Dano, if you read this, I'm ignoring you with dignity. S1K's indeed! :-)
Hi, Bob, glad you jumped in here. As I thought more about it, I realized that a new rotary would have to be made. Not only longer, but the transfer port needs to be re-routed. I thought of a lip seal also, but how do you spec such a thing? Are there standard sizes that could be used, or would it end up being a custom order? One of my first thoughts was a disk with a larger o-ring, although I was thinking plastic rather than brass. But a disk would actually need to be more like a washer, gotta clear that transfer port. Plus, what happens if it gets cocked in the bore, could get ugly fast.
So here's what happens when you send a wood worker to do a machinists job :-)! At least for testing, I'm going to turn a new rotary out of wood. The wood I'm going to use is called Ipe, it's incredibly dense and hard, very stable, and has a very straight, fine grain. Back in the days of steam ships, this stuff was used as bearing blocks for propeller shafts, among other things. And no, it doesn't float. I intend to make it enough longer that it can utilize a standard piston seal, but for the first iteration, no o-ring. Actually, making 6 or 8 will be about the same amount of work as 1, so I may play around with several things while I'm at it. The front breech seal is going to be the biggest problem, too bad it's not on the barrel. So when I come up with the perfect design, then I'll get one of you machinist types to make me one out of metal. That's if I decide I need it, that Ipe is really tough stuff! Later.
Dave