I got back from shooting this morning and early afternoon a while ago - snow-blowed the driveways made a pot of coffee and here I am. Only 3 showed up to shoot today - Hatchet Jack, LB and myself.
Hatchet jack was trying out some of my .400" balls in his coned .40 rifle and they're too tight for it. The angle of the cone must be too slight, ie: too long a taper. The longer it is, the more pressure it takes to get a swaging action going, about directly reversed from what one would think.
To get a grasp on what is required, we look to swaging dies as that is the action needed to load heavy patches and balls over bore size. The ball and patch has to swage into the bore's shape and do it easily enough that we can do it by hand, without the use of a press or hammers. Bullet swaging dies have a very short, properly angled and radiused shoulder inside the die. The die is finished size on one end of the swage angle and larger at the other, just as our muzzleloading barrels are shaped. Movement over the swaging shoulder swages the ball or bullet pefectly with less pressure than would be required with a die having a longer swage shoulder, such as a long coned crown. We found the same problems when attempting to swage .375" bullets for our .366 cal rifles. We should have looked to Corbin's swaging die profiles to see than angles they used in real swage dies so we could duplicate them in our swage dies. Fairly long sloping angles, such as in Lee's lead bullet swaging dies worked with lead bullets only .003" larger than finished size, but when we attempted to swage jacketed bullets down .009", they stuck in the die, or turned into bannanas. Shortening the actual swaging shoulder did the trick - much less pressure was required and perfect bullets resulted. I've found the same typle of swaging shoulder also works well for our muzzleloading balls and patches.
From LB's rifle, the recovered patches showed even cuts of every land. This seemed to happen within the first 6" of ball seating and could be felt on the rod as they were being loaded. If a person could get his hands on some real bullet swaging dies, he'd see the little shoulder. When we get this swaging crown right, we obtain the easiest loading with very tight combinations. In my own .40 rifle, which has a very short cone of perhaps 1/4" total length, loading the .400" balls with a .020" denim patch is only slightly harder than loading a .395" ball with a .0215" patch, yet the .400" ball is already .002" larger than my bore. Crown shape is very important.
