Cylinder Chamfering

[Crow Choker]

You only want to break the sharp edge on a chamber mouth as to much chamfer allows more lateral gas escapement at the gap.

Of the dozen cappers I have, I've never have had a cylinder with mouth chamber's with any burrs or sharp edges left by the factory that impeded seating a ball, not that they don't or have ever existed. Ifin a shooter would want to chamfer the mouth a bit it should be just to take the very sharp edge off if any exist and no more. A ring of lead isn't any written requirement for shooting but an indication that the ball is entering the chamber with a tight fit. I've recovered dozens of balls shot into snow that have no damage but show sort of a flat spot on the sides of the ball where it was swagged into the cylinder and shot down the rifled barrel. I use .380's in 36 caliber, .454's in 44's, and .457's in a ROA. All tight fit in the chambers, no chain fires, no ball movement when other cylinders are fired, and use tight fitting Remington #10 caps on the nipples. In 51 years no issues or chain fires. I do use a lubed felt wad also and have no issues with barrel residue, after alot of shots, clean as the proverbial whistle.

No, that wasn't what I meant. On an unmentionable revolver the chambers are chamfered to facilitate the use of a speed loader.
so, on a CB revolver it makes since to do the same on the feed end to help when seating a ball.

The back end of the unmentionable revolver chambers were chamfered way before speed loaders came about. They were chamfered so as to make cartridge loading faster/facilitate without any bullet tip hangups when loading by fingers.

 

[64Springer]

If I were going through all the trouble of chamfering, I'd use a compound angle.

30 degree and 45 degree.

That would ensure that the ball got pressed in without a ring being shaven off.

 

[user 33697]

There is another reason for chamfering the chamber mouths that Colt did as indicated in his publication - "On the Application of Machinery to the Manufacture of Rotating Chambered-Breech Fire-Arms, and Their Peculiarities, Vol. 11" for the purpose of preventing chainfires.

An excellent explanation to chamfer the cylinder chambers from the original manufacturing process for Colt revolvers.

 

[Dude]

Thank you for that, 1861colt! The question now is - angle and width of the chamfer. What was specified?

 

[Crow Choker]

There is another reason for chamfering the chamber mouths that Colt did as indicated in his publication - "On the Application of Machinery to the Manufacture of Rotating Chambered-Breech Fire-Arms, and Their Peculiarities, Vol. 11" for the purpose of preventing chainfires.

That is an interesting piece of history '61colt. Wherever did you find that. In reading it, the sentence structure and wording sounds like some legalistic, lawyer drawn up report and/or document.

 

[M. De Land]

Along this same line, what should be the angle of the forcing cone? I have one that's a bit rough and needs smoothing. I'd like to turn down a tool with the proper angle and polish with valve grinding compound.

The angle I like for chamfer is 60 degrees included only breaking the sharpness and not much depth. Double tapers are a bad idea in my opinion as the chamfer has to be far to deep to make a second and useless angle.
I once cleaned up a forcing cone erosion perimeter on a model 29 S&W .44 mag and the increase in spitting and gas escapement soon taught me my error. I re-barreled setting back one thread to tighten the new used barrel cylinder gap, re-cut the forcing cone and ball milled the ejector rod housing forward the set back amount. It made a world of difference immediately.
The barrel was 8 3/8s " Smith barrel that had barely been used before the previous owner changed it for a shorter one.
I carry a four inch 629 with Keith loads here in AK for serious stuff but still have that long barrel job for fun shooting with mid-level cast bullet loads..
The cap guns are used exclusively with 3F and lead balls for match work.

 

[Dude]

I just noticed the Colt second generation Dragoon has chamfered chambers. They look steeper than a 45, perhaps 60, and might be 1/32" - just guessing.

 

[Ponderosaman]

I suppose if a person shot conicals, they would be better off with chamfered chambers, so they would have a shot at seating them without them camming in the hole and getting stuck.

 

[n.h.schmidt]

I have had several 70s Euroarms revolvers. They were really cheap .Almost anything you wanted for under $40. All had that chamfer right out of the box. No lead rings ,no chainfires

 

[1861colt]

]

That is an interesting piece of history '61colt. Wherever did you find that. In reading it, the sentence structure and wording sounds like some legalistic, lawyer drawn up report and/or document.

This document was 38 pages by Samuel Colt and a copy is here: https://www.survivorlibrary.com/lib..._rotating_chambered-breech_fire-arms_1855.pdf
He was an Assoc Prof Civil Engineering and received the Telford Medal of Civil Enginering in 1851 from this paper. (Eugene Bourdon also received the medal in 1851 for a pressure guage for liquid, gas and temperature, that is still in standard use today).
The language in the book looking like legalistic language, consider that people talked rather flamboyantly back then as well.

Thank you for that, 1861colt! The question now is - angle and width of the chamfer. What was specified?

I just noticed the Colt second generation Dragoon has chamfered chambers. They look steeper than a 45, perhaps 60, and might be 1/32" - just guessing.

The 1/32" chamfer at 45 degrees in the mentioned 2nd Gen Dragoon, is also shown in Colt's book illustration. It can also be seen in many Colt originals, as I have personally seen in the Gene Autry Museum, where hundreds of percussion Colts are displayed.
As told in the page of Colt's paper I posted above, there were chain fires during the US Army trials, because of flat face chambers sheering the ball. When chambers were chamfered, the balls were swaged and chainfire problems were solved by the combustion blast at cylinder/barrel gap, being deflected away from adjacent chambers. He even put some powder in the other chambers on top of ball that was not ignited. That sounds rather convincing to add the same to our revolvers.