Max pressure question

Elhurron

Elhurron

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Hi All

I have a question regarding cartridge max pressure specs, in this case the 454 Casull. If the 454 has a max pressure capability of 65,000 psi am i correct in assuming that all firearms marked as 454 Casull can handle the max pressure of said cartridge?

Please correct me if I'm wrong.

P.S I'm loading rounds for the Raging Judge Magnum.

Thanks in advance
 
I have pressure tested rounds thousands of times in the lab. There are two "Maximums". The absolute max of a single round, and the maximum average of a 20 round test.

Assume, for a moment, that the single round max is 65,000 (I have no idea of what it actually is.) If you try to load to that limit, the occasional round will be 75,000. This is a no-no.

To answer your question, I would assume that any factory gun chambered in a caliber is safe with factory ammo of the same caliber.

The exception is the odd gun that develops more pressure than it should.
 
sorry for the thread hi-jacking... I have a question along the same lines...

doing some checking on different hodgdon powders, I noticed that CFE223 has a much higher pressure than other powders like varget or h4895... even at max load cfe223 was a good 4000 to 6000 cup higher than the others... how is that safe? is it safe to bring varget up to that pressure then with more powder? assuming that more powder will fit in the case?
 
triple tap said:
sorry for the thread hi-jacking... I have a question along the same lines...

doing some checking on different hodgdon powders, I noticed that CFE223 has a much higher pressure than other powders like varget or h4895... even at max load cfe223 was a good 4000 to 6000 cup higher than the others... how is that safe? is it safe to bring varget up to that pressure then with more powder? assuming that more powder will fit in the case?
Click to expand...

The answer is the limit on the single round max pressure.

If a powder is very, very consistent at max pressure in a given cartridge, the hottest load allowed can be fairly high pressure. But if a powder tends to have the occasional excursion into proof round territory, then the highest powder charge allowed has to be reduced to accommodate it.

This is what a pressure test looks like. Note there is an average pressure and also a single max pressure. The max published load has to keep this single hot round within safe limits.

testdatasheet.jpg


Does that make sense?
 
that makes sense...

so when I was looking at the different powders, I was trying to find one with a medium to lower pressure while still having good velocity. am I going about this all wrong? my thinking behind this is that with a lower pressure it will keep the brass and maybe the barrel in better shape longer and even more important, keep me more to the safe side of the pressure scale until I get more comfortable with reloading... all this research has lead me to H4895, varget, benchmark, H335 and BL-C(2) as the powders I think will work good in both 223 and 308. I have managed to find 335 and 4895 and those are going to be my first and second loads for 223 with hornady 55gr vmax bullets... is there any other powders that people would recommend?
 
For a given MV, the load that uses the most powder (i.e. the slowest powder) will produce the lowest peak pressure. That doesn't mean that it will be the most accurate.
 
For the OP; The strenght of a firearm is tested with a proof load. Each caliber have it's own proof load and under SAAMI there is a min and max proof load for handguns.

For pistols/revolvers, the MAP or Maximum Average Pressure - what Ganderite was talking about - under SAAMI rules is defined as the extreme variation of pressure of ten rounds.

In your case, with the .454 Casull, say the MAP is 60 000 CUP, then, the Minimum proof load for that pressure level is 130% X MAP and the Maximum proof load would be 140% X MAP.
This means your gun may be proofed at one or both min and max, so, between 78 000 CUP and 84 000 CUP.
Each gun is proof tested in both SAAMI and CIP systems.
 
Andy said:
For a given MV, the load that uses the most powder (i.e. the slowest powder) will produce the lowest peak pressure. That doesn't mean that it will be the most accurate.
Click to expand...

IF THE RIFLE IS PROPERLY BEDDED, there is a darn good chance that the heaviest load of slow powder will be the most accurate.
Warren page, nine times winner of the US open bench rest championship and well noted long range shooter, hunter and experimenter, was arguably the greatest rifleman of all time.
I have his book, The Accurate Rifle, and in there he states there is only one way to load the 308 (Winchester)--"Full."
Here is an excerpt from his book on long range shooting.

 
triple tap said:
that makes sense...

so when I was looking at the different powders, I was trying to find one with a medium to lower pressure while still having good velocity. am I going about this all wrong? my thinking behind this is that with a lower pressure it will keep the brass and maybe the barrel in better shape longer and even more important, keep me more to the safe side of the pressure scale until I get more comfortable with reloading... all this research has lead me to H4895, varget, benchmark, H335 and BL-C(2) as the powders I think will work good in both 223 and 308. I have managed to find 335 and 4895 and those are going to be my first and second loads for 223 with hornady 55gr vmax bullets... is there any other powders that people would recommend?
Click to expand...

Yes, you are reading it wrong. the powder with the highest pressure listed would be the powder that was the most consistent. because there are so many variables, the best indicator of a good powder for accuracy (in 308 and 223) would be to research accurate loads.

I load a lot of ammo for those calibers and would suggest the best are Varget, N140, N150, 4895 and RL15
 
.. and theorically, the "best" powder would be the one that fills 100% of the case capacity - when a bullet is seated - and provide the lowest pressure and the higher velocity (within the cartridge standards). In the choice Ganderite proposed, it would likely be RL15 for the .308
But this doesn't mean it will be the one powder to provide you the best accuracy.
 
It has been my experience that many cartridges and rifles give their best accuracy and velocity at or very near max pressure with 100-110% loading density powders. I have experienced this so many times that I automatically go to powders that give compressed loads when I start playing with a new cartridge, and I work up until the cartridge case says stop...........Not some lawyer approved watered down book that is written, more with liability suits in mind than ballistics, and for the cheapest/weakest POS ever chambered in that cartridge by a factory.
I have only ever encountered 2 rifles I could not get excellent or at least reasonable accuracy out of, out of the 100s I have played with.......I consider 1.5" to be reasonable and 2" to be unworthy. One that stands out was a first run Mod 70 Win ftrwt in 257 Bob, absolutely gorgeous rifle but would not keep 3" with anything. Bedded it, floated it, pressure pointed it, tried almost every bullet 100 grns and up with something like 6 or 7 different powders.......she was a no go !! The other was an 8mm RM I put together and the same frustrations, even rechambered and recrowned that one twice, no good, nothing under 3" with that one either. Screwed the 300 WM barrel back on and worked up the first 180gn load with IMR 7828 IIRC and shot a 4 shot 3/4" group at over 3200 fps......took it to Africa a week later (my first foray to the dark continent) and slayed a boatload of critters with it.
 
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