single action army clone

[35 Whelen]

The most destructive "feature" of a single action is the endshake spec. Shooting heavy loads and heavy bullets does exactly the same thing that loose cylinders on open-top revolvers do. The cylinder turns into a slide hammer and beats the revolver unnecessarily.
Imperceptible endshake is best if there's a bushing/ gas ring. In the instance of and open-top with no gas ring, .002" would ( to me) be maximum endshake.

Mike

If you've ever fired a 45 Colt loaded with a 250-255 gr. bullet over a compressed charge of 3Fg, you'd probably agree that it falls in the "heavy load" category!

35W

[M-Tecs]

Friend has one of Great Western 44 Mags. It was the first 44 Mag that I fired. That was in the early 70's and it appeared to be the same size as the 45 Colt Cattleman that dad owned.

https://greatwesternarmsco.com/calibers/44-magnum/

During that time period the Hawes Western Marshal 44 Mags 1873's were common. They were made in Western Germany by J. P. Sauer and Sohn. A college buddy had one.

[Larry Gibson]

Friend has one of Great Western 44 Mags. It was the first 44 Mag that I fired. That was in the early 70's and it appeared to be the same size as the 45 Colt Cattleman that dad owned.

https://greatwesternarmsco.com/calibers/44-magnum/

During that time period the Hawes Western Marshal 44 Mags 1873's were common. They were made in Western Germany by J. P. Sauer and Sohn. A college buddy had one.

I still have one. Got it for my 21st birthday. I've put thousands of "Keith" loads through it. It shows some wear and tear but I only shoot 44 SPL loads in it any longer.

[45 Dragoon]

If you've ever fired a 45 Colt loaded with a 250-255 gr. bullet over a compressed charge of 3Fg, you'd probably agree that it falls in the "heavy load" category!

35W

Oh yes, it will get your attention for sure!!

Mike

[justindad]

It's the diameter of the case and the thickness of the cylinder walls that comes into play here. Not the length of the cartridge.

https://www.engineersedge.com/materi...oop-stress.htm

That is partially correct. However, pressure is not the full story.
*
Modeling the complex geometry of a six holed cylinder as a thin walled pressure vessel is a gross oversimplification, because the variable wall thickness violates the 1:20 wall thickness to radius requirement of the thin wall model. The length of the chamber over which the pressure applies is time varying and also precludes the application of the thin wall pressure vessel model, because the thin wall model requires a very long cylinder.
*
Hoop stress cannot explain axially directed frame stretch and endshake growth before the cylinder cracks. Consider what happens when the bullet hits the forcing cone and the case pressure provides your hands with felt recoil - opposite but not quite equal forces. Consider that the .45 Colt uses heavier bullets and roll crimps.
*
If the only failure mode is cylinder rupture without frame stretch, then pressure is adequate. If Uberti SAA clones experience frame stretch before cylinder rupture, then pressure is inadequate and it is bad advice to say a .45 Colt can withstand 21ksi on the basis of .45ACP cylinders.

[lar45]

Pressure = Pressure .
Have you ever seen a picture of a blown cylinder? They always blow the top off, never have I looked at a picture of a blown cylinder where it split front to back.
Roll crimp or taper crimp does not matter. It's chamber pressure and the strength of the material trying to withstand it.
If you don't like the thin walled Pressure vessel equation, try the thick walled version.

[lar45]

[justindad]

You are right that cylinder rupture is caused by pressure, but incorrect to apply static equations to transient events. This transient event does not qualify for quasi-static equilibrium modeling.
*
If hoop stress was the only factor then frame strength wouldn’t matter.
*
There is more stored potential energy in a .45 Colt load than in a .45 ACP load given the same pressure.
*
I’m applying common sense thoughts here, because modeling stresses in this event is not simple. I’m not putting 23ksi Colt loads in my Uberti.

[lar45]

If we are worried about frame stretching, then the forces applied are "Bolt Thrust". Which is the radius of the case, squared, times pi(3.14 roughly), times chamber pressure. pi*R^2*P = bolt thrust
Again, the length of the case does not matter.
Think of this as a hydraulic ram trying to stretch the frame. It doesn't matter if the ram is 1.00" long or 1.5" long. As long as both rams are the same diameter(45acp and 45Colt are pretty close to each other), and have the same internal pressure(23ksi), then both rams will apply the same force.

[Lloyd Smale]

i was always taught that it was case head diameter not case diameter so a 45 colt loaded to the same pressure with the same weight bullet will have more bolt thrust then a 45acp or 44spec. it was one of the main reasons john linebaugh loaded the 500 at a whole lot less pressure then the 475

[lar45]

i was always taught that it was case head diameter not case diameter so a 45 colt loaded to the same pressure with the same weight bullet will have more bolt thrust then a 45acp or 44spec. it was one of the main reasons john linebaugh loaded the 500 at a whole lot less pressure then the 475

Hi Lloyd, are you talking about the base of the case, or the rim diameter?
I have read that it's the base of the case, or the case head, not the rim diameter.
At one of the Linebaugh big bore seminars in Cody, John had a 500 Linebaugh cylinder that someone had overloaded and it had a bulge over one of the chambers.
The 500 L is loaded to lower pressures because the cylinder wall thickness is less than the 475 L.

[justindad]

You cannot rely on static equations to explain transient events.
*
Consider differences in felt recoil when pressures are the same. The level of pain in your hand is different, do you really think the stress is the same?

[Lloyd Smale]

Hi Lloyd, are you talking about the base of the case, or the rim diameter?
I have read that it's the base of the case, or the case head, not the rim diameter.
At one of the Linebaugh big bore seminars in Cody, John had a 500 Linebaugh cylinder that someone had overloaded and it had a bulge over one of the chambers.
The 500 L is loaded to lower pressures because the cylinder wall thickness is less than the 475 L.

i know john personaly and my buddy was one of his best friends. i had 4 500s and two of his 475s my buddy has 2 475s 5 500s and a 500 max. We have put thousands of 475 pressure level loads loads throgh all thoe 500s with johns blessing and never had a single problem or even sticky extraction. had to be a real idiot that overloaded it. maybe an extreme overload with unique because i really cant see a faster power even being on the bench when i loaded 500s. lars it is rim diameter. theory is the bigger the rim the more it transferred. where it really comes into play is in large caliber lever guns like the 50 alaskan. bolt thrust would beat them up with those loads that tend to start opening the lever before you wanted it to. lucky for my gun was that those loads made me tap out before the gun did. even when rob applegate built me my marlin 94 in 475. i asked him about loads and he told me that the gun would take the pressures of full power 475s but bolt thrust would beat it up with a steady diet of them

[Frank V]

We can argue how much pressure they’ll stand all day. Why do we want to load them to the point of just before they come apart? I’ve shot the .45 Colt for years & for me, I have found there is very little a .454 dia WFP lead bullet at 830fps won’t reliably do. Penetration almost has to be seen to be believed. This velocity can easily, safely, be reached in a Colt SAA that’s in good condition, with several powders. It’s a load that can be shot a lot & is fun & will do 90% of what a six-gun should be called upon to do.
Thanks.

[M-Tecs]

Bolt thrust and PSI of the case head are not the same. Theoretical bolt thrust is calculated by multiplying the chamber pressure by the internal area of the cartridge head. Actual bolt thrust is reduced by case adherence to the chamber walls with the exception of revolvers since the cylinder is basically free floating.

The PSI of the case head for a 45 Colt will be less than a 45 ACP at the same pressure. Bolt thrust increases as the internal area of the cartridge head increases. Internal areas of the 45 Colt and the 45 ACP are basically the same so bolt thrust will be basically equal.

At the same pressure a 223 Rem. will have less bolt thrust than a .223 Winchester Super Short Magnum.

[lightload]

In a New Vaquero 45 Colt, Ruger advises keeping pressure below certain limits. I agree. But please explain how the above technical discussion applies to the the New Vaquero in 45 Colt.

[lar45]

The new Vaquero in 45 colt can also come with a 45acp cylinder. So if it's safe with 45acp at 21kpsi then it would also be safe to load the 45 colt cylinder to 21kpsi.

[DougGuy]

ALL Ruger single action 45 caliber revolvers are rated for 45ACP+P 23,000psi. Matters not 45 Colt or 45 ACP.

[Lloyd Smale]

We can argue how much pressure they’ll stand all day. Why do we want to load them to the point of just before they come apart? I’ve shot the .45 Colt for years & for me, I have found there is very little a .454 dia WFP lead bullet at 830fps won’t reliably do. Penetration almost has to be seen to be believed. This velocity can easily, safely, be reached in a Colt SAA that’s in good condition, with several powders. It’s a load that can be shot a lot & is fun & will do 90% of what a six-gun should be called upon to do.
Thanks.

sure cant argue with that

[justindad]

If Ruger and and Uberti do not claim 23ksi for these 45 Colt revolvers, then either:
1) they are a bunch of doofuses for under-rating their guns, or
2) the fact that transient events cannot be modeled with static equations matters here.
*
I have designed many machines to with stand impacts, shocks, and other transient events. You’d be surprised how many times people tried to use f=m*a to figure the loading in an impact, just to find their designs fail. I hope no one takes advice here over manufacturer’s recommendations and loses their fingers.