Revolver cylinder chamfering question

[Solvo]

.......
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.

[enfield2band]

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.

[vbull]

Well...Just had a close look at a brand new 4 3/4" Cattleman and guess what ? The cylinder is chamfered, just a little but definitely chamfered. I say brand new but it has been in the guys collection for over a year, completely unfired, except proof, boxed and on a shelf in his gun room. Must say I was very surprised but definitely not mistaken and the owner says he's not touched it. The owner is a collector more than a shooter. Seems to me there's no definitive answer to my question on this topic, some prefer chamfered cylinder's for whatever reason's others don't but it looks like Uberti are now in the chamfered camp. Does anyone have an older Uberti they could look at, I'd be interested to hear if this is something they've just started doing or whether they've always done it ?

[enfield2band]

Well...Just had a close look at a brand new 4 3/4" Cattleman and guess what ? The cylinder is chamfered, just a little but definitely chamfered. I say brand new but it has been in the guys collection for over a year, completely unfired, except proof, boxed and on a shelf in his gun room. Must say I was very surprised but definitely not mistaken and the owner says he's not touched it. The owner is a collector more than a shooter. Seems to me there's no definitive answer to my question on this topic, some prefer chamfered cylinder's for whatever reason's others don't but it looks like Uberti are now in the chamfered camp. Does anyone have an older Uberti they could look at, I'd be interested to hear if this is something they've just started doing or whether they've always done it ?

Iv'e got a Uberti New Army police, the one with the fluted cylinder and it is not chamfered.

[loiner1965]

will check my 1858 new army but i am sure its not chamfered

[tacfoley]

I've got just one Ruger Old Army and that isn't chamfered, either.

My Colt Blackpowder Firearms Second-series Walker wasn't, either.

tac

[vbull]

My Ruger and spare cylinder's not chamfered either but interesting about the Cattleman.

[Solvo]

I do agree with the ignition issues from poor fitting caps etc. I should clarify that I refer to flashover on the front end. There is plenty of evidence of issues relating to caps causing the flashover effect.

I Don't grease the chambers either,black power and its substitutes create enough mess without grease everywhere too. I do wonder if this is used in the US in place of Alox where it seems to be common place to grease every time?

For very small chamfers it's quite possible this is a result of de-burring at the factory as a <0.5mm chamfer could be done as part of the process to clean up the machining on the lower cost revolvers.

[tacfoley]

I do agree with the ignition issues from poor fitting caps etc. I should clarify that I refer to flashover on the front end. There is plenty of evidence of issues relating to caps causing the flashover effect.

I Don't grease the chambers either,black power and its substitutes create enough mess without grease everywhere too. I do wonder if this is used in the US in place of Alox where it seems to be common place to grease every time?

For very small chamfers it's quite possible this is a result of de-burring at the factory as a <0.5mm chamfer could be done as part of the process to clean up the machining on the lower cost revolvers.

I don't use grease, but after a dozen cylinder-loads for the last load I fill the small spaces around the front of the ball with Boots E45 skin cream. It's an emulsified emmoluent, and washes away in plain water, taking most of the crud with it.

On the other hand, reading the label inside the Colt case there is no mention whatsoever of greasing - except on the cylinder arbor.

tac

[vbull]

I do agree with the ignition issues from poor fitting caps etc. I should clarify that I refer to flashover on the front end. There is plenty of evidence of issues relating to caps causing the flashover effect.

I Don't grease the chambers either,black power and its substitutes create enough mess without grease everywhere too. I do wonder if this is used in the US in place of Alox where it seems to be common place to grease every time?

For very small chamfers it's quite possible this is a result of de-burring at the factory as a <0.5mm chamfer could be done as part of the process to clean up the machining on the lower cost revolvers.

I think you've hit the nail on the head regarding the chamfer on the new Cattleman as it was only about 0.5mm so it's probably their way of finishing the job after machining the cylinder.