Here's one I just did yesterday, using Taylor's lathe and 320 grit. When I started, it was a normal angled cutter crown as issued on almost all guns from their makers. They can be done this way with just your thumb-end and .320, finishing with something finer, or done more quickly with a latche, of course. Keep rotating the barrel as you progress. The difference in starting the ball and subsequent loading is incredible, compared to a sharper crown. This is not coning per-se, as only the very end of the barrel is shaped,radiused, smoothed and polished, not the interior in depth, like in a cone.
The first one I posted is my .69, done entirely with emery or paper and my thumb. I load a .684" pure lead ball in it with a .030" denim patch. This combination is .030" larger than the groove diameter, for .015" compression per side. It provides the load that shoots into 1 1/2MOA at 200 yards, off teh bags, of course, with the rifle's Express sights.
![](https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv638%2FDarylS%2FP4242099.jpg&hash=5ddc39ebc5bb08f563ca06602830d9976404c0e1)
Here's a closeup, albeit a bit fuzzy, of the same .50 cal barrel.
![](https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv638%2FDarylS%2FP4242100.jpg&hash=0f35fff27678706dbec920a1646c5e72249d8bbb)