Math is math, whether SAAMI agrees or not.Originally Posted by M-Tecs
That shows you how lazy SAAMI is. They also list .303 British and .30-40 Krag with the same max pressure, and they use the same headspace gauge for both, just because the case dimensions are similar.
https://saami.org/wp-content/uploads...sting-Copy.pdf
Page 17 - 30/40 Krag MAP 40,000 CUP
Page 19 - 303 Brit MAP 45,000 CUP
Page 97 - 30-40 Krag headspace 1.787"
Page 107 - 303 Brit headspace 1.8513"
https://www.shootingtimes.com/editor...artridge/99423
SAAMI pressure guidelines for the Krag are lower than for the .303 British. The Krag's maximum average pressure (MAP) is 40,000 CUP compared to 45,000 CUP for the .303. Both service rifles share the single locking lug design, so you'd think they would share pressure assignments. Instead, the difference came down to metallurgy, not parts configuration.
Last edited by M-Tecs; 04-10-2023 at 12:11 AM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
Ok, so they updated it. Great. I don't see how that relates to the portion of my post that you highlighted. Those headspace numbers are interesting, since those cartridges don't headspace on the shoulder, and the headphones gauges don't have a shoulder on them.
Anyway, all that is irrelevant to the OP's thread.
Last edited by Thundermaker; 04-10-2023 at 05:41 AM.
SAAMI specifications are what the industry loads the cartridges to for safety in most all firearms, particularly those the cartridges were originally made for. Yes, there are some exceptions/updates but SAAMI standards/specs are not what certain cartridges can be safely handloaded to in other firearms. The 45 Colt and 45-70 are examples. Consider the 222 Rem and 223 Rem and be safely loaded to US 5.56 pressures when chambered in the firearms (modern actions) that can also handle the 5.56 pressures (not SAAMI standardized). Also, the 303 Brit and 30-40 can be loaded, safely, to higher pressures in rifles such as P14s, M10 Ross's, Siamese Mausers and Ruger SS actions but SAAMI specs for both are held to original specifications for those cartridges.
SAAMI represents the industry not reloaders, so SAAMI specs are, again, what the industry adheres to. SAAMI specifications /specs are also considered as "standards" if any legal litigations come about.
Larry Gibson
“Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
― Nikola Tesla
I recall a friend's experience with pressures. He had bought a S&W M-1917 revolver that appeared clean and tight. Happy with his new purchase, he opened his reloading manual to the "45" bracket, gathered some boolits etc. and set to handloading. When he got to his range and fired the first round with the revolver he thought out loud "I don't remember these having this much recoil and muzzle blast. Same story for the 2nd round but shot #3 was all different. The firearm had become a grenade in his hand: top half of the cylinder was missing, top strap was sheared, total destruction. He gathered his gear and headed back home to his handloading station. When he got there he found his reloading manual still sitting on the bench with weights on it holding the pages open. The top of the pages he had been using for his reference read "45 Colt." And now you know the rest of the story. BTW, this was not the only firearm he overloaded and destroyed with his handloading adventures.
And CUP and PSI still aren't equal.
And NO ONE is claiming they are. They are very different methods to measure pressure. In the 45/70 28,000 PSI and 28,000 CUP have the same number representation. Currently the same for the 45 Colt at 14,000.
The 45/70 convergence at 28,000 with PSI and CUP has not changed since the mid 70's and possibly longer. My references only goes back to the mid 70s.
Currently that also happens with the 45 Colt at 14,000. At one time the Colt was listed at 14,000 PSI or 15,900 cup.
It is somewhat similar to Fahrenheit and Celsius scales convergence at minus 40 F. That means minus 40 F and minus 40 C represent the same temperature/value. What is different with this verse PSI/CUP is that Fahrenheit and Celsius also have the ability to be directly converted. PSI and CUP not so much
Last edited by M-Tecs; 04-10-2023 at 09:11 PM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
Uberti's 1873 Cattleman Callahan model is 44 magnum
Sent from my SM-G781V using Tapatalk
Last edited by M-Tecs; 04-11-2023 at 01:14 AM.
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
"Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
– Amber Veal
"The Highest form of ignorance is when your reject something you don't know anything about".
- Wayne Dyer
Right, but I believe it's an 1873 only in name, and has a much larger frame than a traditional 1873.
35W
The biggest waste of time is arguing with the fool and fanatic who doesn't care about truth or reality, but only the victory of his beliefs and illusions.
There are people who, for all the evidence presented to them, do not have the ability to understand.
NRA Life Member
Yap, Brian Pearce is probably the best source with documentation and equipment for such. He states the Uberti copies are suitable for 45C +p loads. I've been testing the Uberti open-top platforms ( belt and horse pistols) for use with 21,000 psi loads in 45C as well as 23,000 psi 45acp (+ p's) with conversion cylinders ( not the factory conversions).
Mike
They also burst a cylinder when fed so-called Ruger level .45 Colt loads.
To paraphrase Ronald Reagan, the trouble with many shooting experts is not that they're ignorant; its just that they know so much that isn't so.
You know there is a "range" of "Ruger only" loads? It's not just "a" load. As I posted above, I shoot lower end "RO" loads in open-top platform revolvers with conversion cylinders. I wouldn't attempt "upper end" loads.
Mike
I have an old model Ruger Blackhawk in 45 LC and have fired "upper end" loads out of it (WW296 and 250 gr pill). It's absolutely no fun at all - I don't think it's worth loading anything that hot unless you need to shoot lions, and tigers, and bears, oh my...
I’m a bit apprehensive about the idea that a Uberti can shoot .45 Colt @ 21ksi just because it can shoot .45 ACP at that pressure.
1) Force = Pressure X Area, and the .45 Colt has significantly more surface area around the cylinder of the cartridge.
2) I’ve never broken a pistol, but I’ve read that heavier bullets at the same pressure wear a gun out faster. The .45 Colt tends to use heavier bullets. Recoil & momentum matter, so the heavier bullets matter. Also, Kimber told me not to shoot 180 grain bullets in my K6S because they only tested up to 158 grain bullets.
*
Since Uberti is European, their pistols are tested to the CIP standard, which does give you a little bit of head room over SAAMI.
I don't like pushing the pressure in my SAA's more than 8 grs Unique and a 250. No sense in pushing more than that.
That's what I've found also. Once you get outside the SAA loads, recoil gets miserable real quick.
The Uberti 44 magnum is built on a considerably beefier frame and cylinder than the standard SAA. I had one. It's closer to the old original Vaquero in size and thickness of frame and cyinder than the smaller traditional Colt clone SAA.
Got a .22 .30 .32 .357 .38 .40 .41 .44 .45 .480 or .500 S&W cylinder that needs throats honed? 9mm, 10mm/40S&W, 45 ACP pistol barrel that won't "plunk" your handloads? 480 Ruger or 475 Linebaugh cylinder that needs the "step" reamed to 6° 30min chamfer? Click here to send me a PM You can also find me on Facebook Click Here.
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
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
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