Chamfer chambers
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rodwha
58 Cal.
I feel it is wise. It keeps the ring of lead from needing to be dug out of the loading assembly. There’s no real “need” for that ring. There is a need to have a driving band that either will create.
A slight chamfer that still cuts a ring but would also provide a swedging of the projectile. I'd have to look but am sure my Rogers and Spencer is lightly chamfered. Main thing is that the cylinder bore is sufficient that the projectile is slightly over barrel max to insure full engagement.
#1 "There is a need to have a driving band that either will create." :thumbs up:
#2 "Main thing is that the cylinder bore is sufficient that the projectile is slightly over barrel max to insure full engagement." :thumbs up::thumbs up:
"Is it wise to do?" That's entirely up to you. As far as I can determine either will give the same results regarding accuracy. None of the top pistolsmiths associated with the N-SSA doing accuracy jobs chamfer the chamber mouth and I have 2 revolvers done by the late Tom Ball neither of which were chamfered. None of my 20+ revolvers have chamfered chambers but that's just my choice. If it leaves you with a warm fuzzy feeling go for it!
#2 "Main thing is that the cylinder bore is sufficient that the projectile is slightly over barrel max to insure full engagement." :thumbs up::thumbs up:
"Is it wise to do?" That's entirely up to you. As far as I can determine either will give the same results regarding accuracy. None of the top pistolsmiths associated with the N-SSA doing accuracy jobs chamfer the chamber mouth and I have 2 revolvers done by the late Tom Ball neither of which were chamfered. None of my 20+ revolvers have chamfered chambers but that's just my choice. If it leaves you with a warm fuzzy feeling go for it!
rodwha
58 Cal.
#1 "There is a need to have a driving band that either will create." :thumbs up:
#2 "Main thing is that the cylinder bore is sufficient that the projectile is slightly over barrel max to insure full engagement." :thumbs up::thumbs up:
"Is it wise to do?" That's entirely up to you. As far as I can determine either will give the same results regarding accuracy. None of the top pistolsmiths associated with the N-SSA doing accuracy jobs chamfer the chamber mouth and I have 2 revolvers done by the late Tom Ball neither of which were chamfered. None of my 20+ revolvers have chamfered chambers but that's just my choice. If it leaves you with a warm fuzzy feeling go for it!
Out of curiosity are the chambers typically bore diameter or better for those participating in the matches?
My Uberti revolvers do not have a chamfer. My Euroarms Target Model 1858 Remington has a rebate in the chamber. It should help to insert the ball or start a bullet.
I've posted this picture in other messages, but I thought to post it again here.
The mouth of the cylinder is rebated. the diameter at the mouth is 0.456" and the chambers measure 0.440". This gives me a volume for my powder for 27 grains of 3fg.
I can see a distinct edge where the rebate ends and the chamber begins. This appears to be matched fairly well to the barrel bore (land to land) size of 0.447"
The mouth of the cylinder is rebated. the diameter at the mouth is 0.456" and the chambers measure 0.440". This gives me a volume for my powder for 27 grains of 3fg.
I can see a distinct edge where the rebate ends and the chamber begins. This appears to be matched fairly well to the barrel bore (land to land) size of 0.447"
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I have a 40 year old ASM 1851 Colt clone that is chamferd. I have seen others of that era that also had that.
n.h.schmidt
n.h.schmidt
I don't think Samuel Colt chamfered his chamber mouths?
Richard/Grumpa
Richard/Grumpa
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A bud played with chamfering on a number of his guns. He REALLY liked the way the chamfering swaged the ball going into the chamber rather than cutting rings.
There's a down side you kinda need to watch for in his experience though. The tolerances for fit between cylinders and barrel throats are about as sloppy as political promises, depending on the manufacturer, model and individual gun, and whether or not the barrel throat was squared off or had a bit of a tapered lead.
I don't recall the specs he worked out, but he found that with larger gaps you get a lot more blow-by (or crap and corruption, as he called it) after chamfering. No problem with closer cylinder/barrel gaps or barrels with a tapered lead, but beware of bystanders and shaved lead if you chamfer the chambers with a large cylinder gap and squared off barrel throat.
In all honesty, I see no reason for chamfering of cylinders.
From the early Colts up to now, the manufacturers did not chamfer their cylinders. There must be some reason.
If you look at custom revolvers, Haegerman for $1,000, they are not chamfered. Neither are the Pedesoli Remington 1858's which if you can find one bring a premium. Ruger Old Army's are considered the premium revolver for line matches, they are not.
Folks worry about chain fires and they wish to modify their cylinders, why?
From the early Colts up to now, the manufacturers did not chamfer their cylinders. There must be some reason.
If you look at custom revolvers, Haegerman for $1,000, they are not chamfered. Neither are the Pedesoli Remington 1858's which if you can find one bring a premium. Ruger Old Army's are considered the premium revolver for line matches, they are not.
Folks worry about chain fires and they wish to modify their cylinders, why?
Sam Colt had a patent for chamfering chamber mouths in 1837. He created the chamfer to help prevent chain firing.
He thought the blast of flame coming from between the face of the cylinder and the rear of the barrel was being directed down past the swaged in ball/bullet and that by chamfering the chamber mouth the blast would be deflected away from the ball.
These chamfer's were very large. Based on the drawing I would say they were about 1/16 X 45°. They were not the little "edge break" we usually think about using
Link to article about this. If you follow the link and your on a computer hold down the ALT button and hit the + button to enlarge the text.
https://books.google.com/books?id=T...l Colt patent chamfered chamber mouth&f=false
Another link to the patent:
https://patents.google.com/patent/US1304A/en
Apparently he didn't use this patent on many of his pistols because I've never seen a reference made to it in any books about collecting Colt pistols.
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Zonie is correct. Colt mentions it also in his treatise "The application of machinery to the manufacture of rotating breech firearms". The idea was that the angle of incidence being equal to the angle of reflection the chamfer would redirect the fire. Colt stated that it worked so well that loose powder placed in an adjacent chamber was not ignited. True? Who knows. Colt used a similar method to address fouling on the arbor binding the cylinder by turning a reduced diameter ring on the arbor in front of the cylinder. This is still present on some reproductions today.
Thank you, Zonie, and Denster. I am delighted to learn this, I had never seen it before. Also, I shall have to read it further, so that my non-mechanically inclined mind may better understand the workings of Colt's revolvers, and his reloader (which I have seen at the museum in Paterson).
His reasoning for the chamfer was that it would redirect the combustion gasses away from the adjacent chambers, thereby preventing chainfires. Am I correct in concluding that he did not use this chamfer in production because the same end was achieved by use of an oversized ball being cut to a friction tight fit in the act of seating, eliminating the extra step of cutting the chamfer?
Richard/Grumpa
His reasoning for the chamfer was that it would redirect the combustion gasses away from the adjacent chambers, thereby preventing chainfires. Am I correct in concluding that he did not use this chamfer in production because the same end was achieved by use of an oversized ball being cut to a friction tight fit in the act of seating, eliminating the extra step of cutting the chamfer?
Richard/Grumpa
Redirecting the chamber gasses away was the idea but as I said, I haven't seen or heard of any of Colts pistols that actually had that large chamfer on the chamber mouths. It should be noted that Colt's patent on the chamfer was dated 1837, when the Paterson was in production (1837-1840) and a lot of the Paterson features were never carried into the later Colt pistols.
I have seen a few Colts that did have the sharp edge of the mouths removed with a very small corner break that would tend to fold the ball's lead out of the way rather than shear it off like a sharp edge would do. It might have been done at the Colts factory or maybe it was added later in the guns life by a gunsmith?
Because of leads very low yield strength vs it's tensile strength, its ability to "spring back" or retain the force due to compressing it with a "lead in chamfer" is very low if not non-existent. In other words, when lead is moved, it just stays moved and it really doesn't try to return to its former shape.
Because of this I think a lead in chamfer won't cause the lead to try to grip the walls of the chamber any better than if it was just sheared off as it goes into the chamber.
Of course, there's nothing wrong with trying a small corner break on the chamber mouth. It won't hurt anything to have it.
I have seen a few Colts that did have the sharp edge of the mouths removed with a very small corner break that would tend to fold the ball's lead out of the way rather than shear it off like a sharp edge would do. It might have been done at the Colts factory or maybe it was added later in the guns life by a gunsmith?
Because of leads very low yield strength vs it's tensile strength, its ability to "spring back" or retain the force due to compressing it with a "lead in chamfer" is very low if not non-existent. In other words, when lead is moved, it just stays moved and it really doesn't try to return to its former shape.
Because of this I think a lead in chamfer won't cause the lead to try to grip the walls of the chamber any better than if it was just sheared off as it goes into the chamber.
Of course, there's nothing wrong with trying a small corner break on the chamber mouth. It won't hurt anything to have it.
I wonder about chamfering a chamber that might be slightly out of round (repros), would the lead ball be sufficiently deformed in seating it to seal off the chamber from the flame?
Richard/Grumpa
Richard/Grumpa
arcticap
54 Cal.
It's a controversial subject.
The best advice that I've read is to not do it unless there's ball creep during firing that can be attributed to a problem at the front of the chambers such as overhanging metal or burrs.
While some people do it for other reasons, the adage "If it's not broken, don't fix it" can be applied.
2nd hand information said that Colt's early patent was the result of chain fires that occurred during gov't. trials to obtain a contract which caused the Paterson to fail.
Colt ended up going out of business without a contact and did not try to renew that patent like he did with some of his other patents.
The patent may have been an attempt to fix a problem that was unique to the Paterson, which later patents, improvements and models helped resolve.
Also mentioned was that force testing showed that a swaged ball requires more initial force to expel it from a metal tube compared to a ball that's cut or sheared.
My opinion is that if the walls of the chambers are parallel and within spec. then that may negate any need to chamfer the cylinder mouths.
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