It's tapered and does seem to stick out of the breech plug hole a wee bit more than a Winchester 209, so it does seem the diameter near the rim is a tad bigger. The action still closes fine and it still goes pop. Can't really tell if it's a more robust pop than the Winchesters or not. There's not a lot of reviews of them in muzzle loaders, though the few I've found are generally good, except for occasional size issues. There seems to be universal agreement about their quality, though. I'm glad to have found them.
