Percussion Revolvers

General => General => Topic started by: tscmmhk on December 23, 2013, 06:35:28 PM

Title: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: tscmmhk on December 23, 2013, 06:35:28 PM
I own several different brands (Pietta & Uberti) cap / ball revolvers and all of them have undersized cylinder chambers. For example, the Pietta 1860 Army has cylinder chambers that measure .443" / .442". I have slugged the bore on the 1860 and the groove diameter is .452". I'm certainly OK with the barrel groove diameter at .452" but why are the cylinder chambers almost .010" smaller? There might be a reason but I haven't figured it out yet. I'm guessing it might be a lawyer thing but then i would only be guessing. All of my revolvers have smaller cylinder chambers so it isn't necessarily a Pietta problem because the Uberti revolvers have the same issue. Does anyone know the reason they make C&B revolver this way?

Thanks,

Tom
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: swathdiver on December 23, 2013, 10:11:34 PM
Probably to cut down the pressure if some yahoo puts too much Triple 7 in it.

I have several .36 caliber revolvers from Pietta and ASM and they all have chambers larger than groove diameter.  Years apart, a Pietta Colt and Remington have .369 chambers and .367 groove diameters.  They are tack drivers!  The ASM has .374 chambers with a .372 groove diameter and it too is very accurate, especially with its faster 1:21 twist.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: StrawHat on December 28, 2013, 06:56:55 AM
The undersized chambers predates 777 by a long time.  I recall more than a few competitiors boring the chambers to a larger diameter on original Colts and Remingtons when they were popular on the firing line.  It might be that was the way the originals were built and therefor the way the replica makers built them.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: Hoof Hearted on January 07, 2014, 07:47:27 AM
My opinion is that the chambers are bored "tighter" to cause "shaving" of your balls!

This stands to reason in today's litigious society and it reduces the chance of chainfires. If the makers were concerned with accuracy they would do many things differently..............

HH
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: tscmmhk on January 10, 2014, 09:34:43 PM
Based on what I have read and people I have personally talked to, I decided to ream the cylinders on three of my Cap&Ball revolvers to prevent "shaving" my balls. ;) The Pietta 1860 Colt Army, Uberti 1858 Remy and my Pietta 1858 Remy got a cylinder ream job. I did the work myself using a Manson piloted .452" cylinder throat chamber reamer from Brownells. Took about a hour to complete and I must say the Manson tool does a nice job.
The next part is to wait until the weather gets better and go try all three revolvers at the gun range. Hopefully I'll see some improvement in accuracy.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: long hunter on January 10, 2014, 11:29:16 PM
You still need that "shaving". That's what prevent chainfires. If your chambers are .452, you need a .454 ball. Chamfering chamber mouths helps too.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: tscmmhk on January 11, 2014, 07:45:08 AM
I'll be using .457" lead round balls for sure and yes I chamfered the chamber mouths slightly to help swage the lead ball. That should give me a good seal to prevent a chain fire.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: curator on January 11, 2014, 11:04:24 AM
Hoof Hearted has it right. The Italian manufacturers want to be sure litigious Americans won't have chain-fires. They also know most revolver buyers will not shoot these guns very much and will be satisfied if it goes BOOM and they occasionally hit something. When I was working in the museum business, I miked many, many original C&B revolvers' chambers and bores. I rarely encountered one that had chambers smaller than bore size. The one I did find had a miss-matched cylinder based on serial numbers, and that on a Manhattan Navy, was only about .002" under. Italian replica C&B revolvers' chambers vary from .002" over (special "shooter models') to about .006 under. Nothing compares with My ASM Walker that had .446" chambers and .468 groove barrel. Balls pushed out of the chambers would free-fall down the barrel.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: Frank Graves on January 11, 2014, 05:57:47 PM
At The Gathering of Patersons at the 2008 meeting of the Texas Gun Collectors Association, I measured the chambers of the cylinder and the corresponding barrels of the original #2 and #3 Belt Model Colt Paterson revolvers there as there was a similar rumor about the Colt Paterson revolvers.  Without exception, each cylinder's chambers measured about .0125" to .0150" LESS than its matching barrel, land to groove.  Either Sam Colt thought the bullet would expand upon the powder charge igniting as it entered the barrel, or was fearful of too much pressure as is the thinking here about the replicas.  It was such an early time for the repeating revolver in 1836, either could have easily been Colt's motivation.  Iron was a lot softer and more inconsistent back then.  Interestingly, the caliber for this revolver is listed today at either .31 or .34.  I guess it depends on whether you think the caliber of the gun is the diameter of the ball that you put in the cylinder, or the diameter of the barrel at the muzzle.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: Jaxenro on January 12, 2014, 04:20:56 AM
What I never understood is why doesn't some gunsmith specialize in reaming cylinders to the proper size. Seems like it would be a quick fee $$$ every week as someone is always asking
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: The Old Man on January 12, 2014, 04:49:05 PM
I have a Euroarms 1858 that was made in 1974. It's chambers are .450    The groove dia of the barrel in .450 also. The
chambers are champered.


(http://i119.photobucket.com/albums/o127/prizzel/91715dd7a59e1df263a2b18e817849e8.jpg)
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: swathdiver on January 12, 2014, 10:12:36 PM
Have recently come across 3 ASMs with chambers way over groove diameter, a Navy 4 thousandths over and a .44 brasser 1860 5-6 thousandths over.  Then there's another 1860 with a .4575 groove diameter barrel with .447 chambers!  LOL

Then there's the ASM Walker with the chambers .001 over and it's a tack driver and tight enough to shoot .451s.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: tscmmhk on January 13, 2014, 12:27:42 PM
After all the responses to my original question I have come to the conclusion that Italian repro revolvers are all over the place as far as cylinder dimensions. It also looks like the lawyers have got their sticky fingers in the mix to prevent law suits. ::) I have heard the opinion on other forums that most Italian repro revolvers today are about 90% finished /fitted. With my limited experience with cap&ball revolvers I couldn't agree more. Some of us have become amateur gunsmiths out of necessity but then that's not a bad thing.
One question I do have is there any book(s) or document(s) that captures all these gunsmithing tips dealing with cap & ball revolvers?
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: Jaxenro on January 13, 2014, 12:59:34 PM
Not that I know of but I have a few pdf's I collected
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: The Old Man on January 13, 2014, 07:24:52 PM
Well in my 50 years of being in this game, I have had several brands.  I have had all of them
apart doing things like lighter trigger pulls and replacing stuff when it breaks. All of the inside
parts look like stamp metal. Except one. And that is the one I bought about two years ago for
85.00.  I had just finished shooting the "As Issue" matches at the Nationals at Friendship In.
and I was sitting at a picnic table next to the range. I took it completely apart. I used to work in
a tool & die shop for 20 years in quality control so I know what good machining looks like. Well
the hand, trigger, and bolt all looked they were machined . I have never seen anything like it.
Either someone did machine these parts, or it came from the factory like this. What kind is it
your asking. Well it is the Euroarms made in 1974. How did I do you ask. Well I won two 1st place
gold medals. It does shoot and had a very light 1 1/2 lb. target trigger. I don't know if all Euroarms
made in the early 70's are like this or not. Never have seen another one. If any of you have one
let me know. There is a picture of it in the thread up a little. I did the de-fared and the antique
look.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: swathdiver on January 14, 2014, 11:50:18 PM
ASP/Euroarms did make a shooters revolver that was advertised with a tighter twist barrel, maybe a Lothar?  Do not recall them mentioning the internals.

I have a book/manual from S&S Firearms called Cap and Ball Revolver Servicing.  It's quite thorough and well worth the money. 
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: tscmmhk on January 29, 2014, 09:53:40 AM
Thanks Swathdiver,

I just received the Cap & Ball Servicing Manual you spoke about and I must say it has a lot more information than I expected. Thanks for sharing.
Title: Re: Why do Italian Repro Revolvers have undersized cylinder chambers?
Post by: Kaido on January 01, 2015, 03:34:19 AM
The situation with Older Produced Percussion Replica Revolvers, had several complications amongst them Legal, Liability . The fear of being sued etc. Many early Produced Percussion Revolvers had smaller frames, barrel and cylinder boars and had metal steps in the cylinders so one could not place maximum powder charges in them. From what I have seen Original Percussion Revolver from the 19th Century were over all larger and had bigger bore diameters as well as deeper cylinder chambers, some say even on the originals the Cylinder walls were tapered had steps, from what I have seen that was not the case. The Replica Percussion Revolvers made after the year 2000 from what I have seen, have now larger frames and the cylinder bores are bored strait and down low as possible to the start of the threads of the nipples. Pietta Uberti made Replica Revolvers have the Cylinders bored strait and are large. Some say this came into being with the advent of Conversion Cylinders that would now require a stronger frame and overall gun. I am very Pleased that Pietta/Uberti etc now make their Percussion revolvers this way, as it is line with the Original sizing and allows for more powder to be used in the cylinders. That is important for people wishing to use a Percussion Revolver as a Hunting implement especially for Big Game Animals. With the development of hotter powders and propellants that are also in line with the 19th century fine sporting pistol powders and the invention of my Universal Bullets for Hunting use, today's Percussion Revolvers have become real choices for the hunter to take afield weather as a backup side arm or as a main hunting implement they are Big Medicine!. So the New Deeper Strait walled Cylinder Chambers are a great improvement that should be retained and not done away with. Kaido Ojamaa.