Dragoon, yes I just changed the nipples on my Pietta .58. I ordered them from Dixie. The ad says these nipples (Ampco) are made from a high tensile strength alloy, 118,000 psi,which is stronger than most barrel metals and is resistant to erosion. The base hole is .028 inch which is supposed to reduce blowback and concentrate the flame into the charge. The size I ordered was 6mm x .75 , the part number is NP1080.
I haven't shot the gun since I installed the nipples but have popped a few caps while fitting my hammer face to them. They are a golden color, makes the pistol look like it's capped if you don't look too close, and they have a very smooth finish. The ad says no. 11 caps fit them. I only have the new Remington caps on hand so I can't say about other brands but # 11 Remingtons are loose. They'd probably work in a "pinch" but the nipples are so slickly finished I would be afraid they would drop free. The #10 Remingtons slide on with just a touch of resistance and bottom out with thumb pressure. I used kitchen matches to soot up the back of the nipples when I fitted the hammer face so the gold color isn't showing right now, but they looked a little out of place on my antiqued Remington. I hope they discolor some after they get fired a little.
Low Key, I could picture the scene you wrote about the group all being asleep leaning against the wall. There is only one problem with the concept, though. In any group of sleeping geezers which consists of more than three individuals, at any given time at least one member of the group will be awake going to, coming from, or trying to recall if they went to, the bathroom. In a western setting, if we go the R rating route, and the wall's right there anyway, at least we could keep the group from wandering off.
Steve