Quote Originally Posted by loiner1965 View Post
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As most revolvers come from the Italian factories, the openings of the cylinder chambers are machined with sharp edges. These sharp edges bite into the soft lead of the ball as the ball is started and when the ball (or conical) is rammed down, the ball is cut leaving it undersized and unsymmetrical thus creating a gap where hot gas from another chamber can enter and ignite the charge. You can vastly improve your revolver by using a countersinking tool to remove the sharp edges at the entrances of the chambers. It is easy to do and only takes a couple of minutes. Simply hold the cylinder in you left hand and carefully grind with your right hand until the sharp edges of all six chambers are removed. When finished, your cylinder chambers will be lightly ‘chamfered’ and no more than a light chamfer is needed. This operation will not disfigure your revolver in the slightest.

Chamfered cylinder and countersink tool.

Chamfering the chambers does three things for you. First: instead of shaving off a lot of lead and ending up with an undersized, unsymmetrical ball, the ball is ‘swagged’ into the hole, thus making a perfect gas tight seal (assuming no trapped powder grains). Second: because you don’t shave off so much lead, but gently swage the ball in place, the rammer force is usually less. Third: because the ball is not undersized or unsymmetrical by having been cut, it fits the bore and engages the riflings much better. When a ball fits the bore and engages the riflings properly, you get a much more accurate shot.
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.