Quote Originally Posted by Solvo View Post
I don't have a depth of experience in manufacturing or gunsmithing, but from what i do know about machining and physics this is, to be polite about it, on par with fertilizer.

To address the points:
First.
The ball is cut, but it cannot be undersize... it's being cut by the hole it's forced into, It is the exact right size for the chamber. Unless the chamber is conical for some reason, in which case a chamfer will just allow the ball to swage to the same size and have the exact same result. Lead doesn't magically expand like that.

Second.
Reforming instead of cutting is also likely to increase the rammer force - I'm not certain on this so wont debate it, but shear force to trim a tiny ring of lead vs swaging the same amount and increasing the surface area would increase friction - all this by such a minute amount i highly doubt anyone would ever notice.

Third.
It's not undersize. Also this is why cap and ball revolvers use a 'forcing cone' to further reduce the diameter of the projectile and tightly fit it to the rifling.

This whole post seems to have been taking from a US forum where they have an obsession with the idea of flashover and very little idea of how metal works. Not to mention a fairly insulting opinion on firearms design, it's entertaining how some people think this "one simple trick to improve your accuracy" is something never before considered in the last two hundred years. I'd be willing to bet that the combined efforts of designers like Samuel Colt and the cast majority of western worlds armed forces might have noticed if the design was as terrible as this person seems to suggest.
I agree with what you are saying. The chamfer on the mouth of the cylinder may locate the ball on the chamber easier but you are still swaging the ball into a fixed diameter chamber and it will always be the same size as the chamber.
The ring of lead that is taken off is so that the ball seals the chamber because it has been swaged in,as you know.
I have witnessed flashover. It was from the back of the cylinder. Loose fitting caps or worn nipples that allow hot gases in from the previous shot are going to be a problem.
I have never used grease on the front of the ball and nor do most people I shoot with. If you grease the balls and fire one shot and then look at the chamber either side most of the grease will have been blown out, which illustrates that gas pressure is deflected back into the front of the chamber. If swaging the ball in did not effectively seal the chamber flashover would be a very common occurence.