How thin is too thin?

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foolzrushn

New member
My 1981 Navy Arms 1851 Colt Pietta is .44 caliber. I have read on this forum that Pietta just took the .36 caliber barrel and drilled it out to .44 caliber for marketing reasons. I believe that and see how that could cause the machining on the .44 caliber barrel to have a wall thickness that is thinner than that of the .36 caliber. Unfortunately bigger means more powder to those who just fill the cylinder chamber to the top. Is it safe?

What I am wondering is if the later (newer) Piettas have the same thin spots in the construction of the barrel that my 1981 version has. The three spots that concern me are: the front sight dovetail cutout, the cutout in the bottom of the forcing cone for the cylinder arbor and the wedge screw cutout (threaded hole) inside the arbor cutout.

I don't know how much thickness is required...that would depend on the charge. Perhaps even .060 is plenty. That's what I measure at the cone. It looks like the screw cutout would make that even thinner though. At least on my gun. I suppose that the configuration has remained the same because of the limits of the Colt shape.

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What say ye?
FRN
 

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B

Bishop Creek

New member
Just curious, as they don't come stock that way. Looks like a nice job.

Edit, I meant the inside rim of the muzzle, not the outside of the barrel.
 
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D

Driftwood Johnson

New member
Howdy

You are over thinking this. The pressure is greatest when the ball is still in the chamber. Once the ball starts traveling down the barrel, there is less pressure.
 
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foolzrushn

New member
Still would like to know if the more recent production .44's are just as thin in those spots. I was under the impression that these repo barrels are pretty soft, and derive their strength from thickness.

Personally I see no point in heavy loads, after the first time to assure yourself. After that it just causes more fouling, or loosens things up or costs more. But thats just me. I would like to find the most accurate load however....wherever that falls for this gun. I am ready to start finding that load again if it stops raining long enough for me to keep my powder dry.
FRN
 
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DPris

Member Emeritus
As mentioned, the pressures are highest at the moment of ignition, when the ball's still in the chamber.

Compare the thickness of the chamber walls to the thickness of the barrel walls at its thinnest point (or points).

The barrel will generally be no softer than the cylinder.

If the thinnest part of the barrel at any one point is equal to or greater than the thinnest part of the cylinder wall (typically at the bolt notch cut), then the barrel will be at least as strong as the chamber in dealing with ignition pressures.

Denis
 
B

bedbugbilly

New member
Lawyers have been around for a long time . . . that would have been pulled for liability reasons if there had been any inkling of problems.

As mentioned - take a look at a modern revolver or semi-auto. A .380, 9mm, 45 ACP - and they all develop much higher pressures than the black powder in your revolver.

I can't answer your question as to whether they still make them with the same "wall thickness" - stop in at a LGS or Cabbalas, etc. and ask to see one if they have one in stock. As far as loading heavy during your first firings and then cutting back so you are "assured" there won't be a problem . . . I fail to see the difference if you are holding the handgun during the first firings? Unless you tie it to a tire with a string on the trigger? Years ago, when I was building ML rifles, if I had an "unknown" barrel blank . . . I breeched it, tied it to a tire and triple charged and triple balled it and set it off with a piece of cannon fuze. I never had one "blow".

C & B revolvers are not the only ones that are "the same" but just bored out for different calibers. Cagridge handguns such as the Uberti "cattleman" are the same way - same barrel and cylinder outer dimensions, same frame - but they are chambered in everything from a 32-20 (32WCF), 38, 44, etc. up to and including 45 Colt. All are "proofed" and made to be safe . . . otherwise, the lawyers would make sure they weren't on the shelves.

If a person doesn't follow the manufacturer's recommendations for loading, ammunition, etc. . . that's a different story. As they say . . "you can't fix stupid". More than one has been blown up where a person reloads their ammo and they dropped a double charge and didn't catch it. THAT can cause a problem! :)
 
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foolzrushn

New member
I really did think about firing this one with a string the first time, before I even noticed the thin spots. It was my first BP firing.....well Pyrodex.

Don't modern barrels use improved alloys? Not apples to apples is it? Cabela's probably won't let me remove the loading lever on their new gun.

Mine didn't blow up and I don't expect that it will, but I am very curious whether the new 1851's somehow have increased the thickness in those areas. Possibly a smaller diameter shank on the wedge screw?

I also want to know how thin mine is at the wedge screw cut. Can't really get to the threaded hole very well, but maybe I can get some pictures.
 
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DPris

Member Emeritus
Improved, compared to what?

Modern percussion revolvers will tend to use a "better" formulation of steel than the originals, in terms of strength & consistency, but still are not heat-treated to the same level as a modern handgun.
That's as a general rule.

I have an old Euroarms .36 Remington that I had the cone opened up a shade on to compensate for slight chamber mis-alignment.

The gunsmith was surprised at the barrel hardness, said the repros are usually a little softer.
It can vary.

I really wouldn't obsess too much over your barrel.

As a rule, it's likely to be no softer than your cylinder & it's the cylinder that takes the brunt of the pressures.
Same deal whether BP, Pyro, or other.

The maker would not have sent the gun out in a condition that involved obvious risk.
Denis
 
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Fingers McGee

New member
My 1981 Navy Arms 1851 Colt Pietta is .44 caliber. I have read on this forum that Pietta just took the .36 caliber barrel and drilled it out to .44 caliber for marketing reasons.
Click to expand...

I'm afraid your source and the premise about thin spots when comparing .36 cal and .44 cal barrels is bogus. Measuring a Pietta .36 and .44 1851 Navy barrel across the flats indicates that the .36 measures .620 inches and the .44 .670 inches. Wall thickness on both is .122.
 
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