Pressure & Powder ?

Harve Curry · Jun 17, 2005

I'm familiar with powder burn rate charts, most of us are.

But is there a chart that shows the pressure curve of powders?
or,
At what pressure curve does a specific powder burn efficiently?

Most powders have a begining pressure that they do well in, and an end pressure that it does well in. Then as components change (more powder, heavier bullet, etc.) the pressure increases to the point where it's out of the efficient operating range of that powder, accuracy drops off, pressure leaps, and another powder will most likey be more suitable for the purpose.

caz223 · Jun 17, 2005

I know it's not exactly what you're looking for, but midway's loadmaps give pressure in PSI and velocity with every INCREMENT in a powders safe range.
They don't list every powder, but the data they list on the powders/bullet combos is pretty close to what you're looking for....
I think you could actually plot a pretty good chart from their data...
The problem is....
The pressure is not only a function of the powder, but the bullet, and prolly lots of other stuff, too...

1911 guy · Jun 17, 2005

caz223

hit it on the head. There are many variables that affect pressure. Bullet weight, seating depth, primers, case capacity, and probably some other obscure things I don't know will all affect pressure. That's maybe why manufacturers shy away from pressure tables.

Jim Watson · Jun 17, 2005

This used to be a fairly common concept among handloaders who went beyond the recipes. Elmer Keith refers to the "balance point" of a powder as the chamber pressure at which it is the most efficient, with a "working range" above and below that where changes in powder charge are accompanied by a more or less proportional response in pressure and velocity. There are so many more powders available now, and so many people with other objectives in mind that the notion has pretty much passed out of use.

Harve Curry · Jun 17, 2005

Thanks Jim, 1911, and thanks for the info caz223.

It would be nice if powder manufacturers listed in chart form , the optimum pressure that each powder burns at efficiently. For the purposes of a chart the cartridge should not matter, each powder has a pressure curve that it performs in.

bakert · Jun 23, 2005

Don't know that I would trust a chart like that too much. Some powders spike like crazy at certain points. Like was said way too many variables even in different guns of the same make.

WESHOOT2 · Jun 26, 2005

ditto

".....way too many variables....."

Way. :banghead:

Harve Curry · Jun 26, 2005

I guess I'm not being clear.
All powders have a optimum pressure range that each powder is designed to burn and expand within.

redneck2 · Jun 26, 2005

Well....OK.....now, how does one measure the pressure??? Case head expansion has been proven to be pretty much bogus

Only thing I can think of is velocity/caliber/ bullet combo if you had a benchmark

Pressure & Powder ?

Harve Curry

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1911 guy

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Jim Watson

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