Powder versus pressure info

[Wolfer]

Most of us that have been at this a while know that every powder has a pressure range that it works best in. Some powders have a fairly wide range while others not so much.
I can't recall ever seeing anything that listed ideal pressure ranges. I've always used burn rate charts to try to get a feel for a new powder I wanted to try
Does anyone know of published data on this?

[Rocky Raab]

It isn't published but a little thought as to the intended use will tell you most of what you want to know. Look at the SAAMI pressure ratings for cartridges as follows:

Shotgun/handgun powders have a design operating pressure in the 10k to 15k region.

Powders for small rifle rounds of the early 20th century work in the 30k to 35k region.

Powders for WWII-era rounds are designed for 45k to 50k.

Powders for almost all modern rounds are optimized for 60k to 65k pressures.

[felix]

Good observation, Rocky! ... felix

[btroj]

Rocky, nice list.

I also look at the powder manuals to get a feel for which powders seem to handle reduced loads well. Not all powders are safe with reduced loads.

[Larry Gibson]

Rocky's list is more a function of the cartridge/shell and firearm capabilities to handle pressure safely than of powder pressure range .

Besides the powders content itself (double or single base, deterents, flash retardents, etc.) external factors control the effective pressure range; force and duration of primer flame, loading density, weight of bullet, friction coeficient of the bulet, etc.

There probably is not such a list because of the large degree of variables would make such a list almost impossible to do accurately. There would simply be too many exceptions and crossovers.

Larry Gibson

[felix]

Like medicine (all designer chemicals, actually), powder is designed to meet a specification, such as case size, bullet, and gun. Aspirin works fine for some headaches, but not for others. Depends on the person as well, right? ... felix

I just thought of a rare converse. The nuke bomb. The "powder" came first, and then the "gun" was designed to make it work. Did you not know that the gun was designed by several graduate students, all under 30 years old, selected from all over the country by Oppenheimer? ... felix

[Rocky Raab]

It works both ways, Larry. The powders are designed to work optimally at the pressures those rounds work at.

For example, RedDot, 700X, Clays, PB and many others were "specced" to burn best at shotgun pressures. That makes them equally suited for standard or "Special" handgun levels.

4227, 4198 and similar powders were designed for Hornet/Bee and similar rounds that run in the mid 30k pressure area.

Powders like 4895, 4320 and 3031 were created for .30-40, .30-06 and similar rounds that then ran in the mid 50 to 60k.

When "mangleum" rounds and high-intensity rounds like the .270 came in, pressures went up to the 65k region as standard. And today's powders burn best in that zone.

[Larry Gibson]

However, Rocky, all of those powders will still burn efficiently at 60 - 65K psi. Let's look at 4 very old smokeless powders still in common use today; Unique, 2400, 3031, 4895 and 4831.

Unique will ignite easily and burn efficiently from 6-7K psi upward of 60-65K psi.

2400 ignites easily but doesn't start burning efficiently until 20K+ psi and will do so up through the same 60-65K psi.

3031 and 4895 will also start burning efficiently at 20K+ psi up through the same 60-65k spi in magnum cartridges (not the best application for either powder).

4831 is a very slow burning powder and will not burn efficiently until psi is above 30-40K depending on load density, expansion ratio and bullet weight used. It performs best in the 60-65K psi range.

Note also that most of the powders slower than 4831 and many ball powders, especially the slow medium to slow burning ones, do not ignite efficiently in many cases in many uses.

Point being, if we take an old cartridge like the 30-06 and a modern cartridge like the 300 WSM both in modern bolt actions, all of those powders and, in fact, all of the smokeless powders we use will ignite and burn efficiently at the top end up through the 60-65K psi range (or above if anyone foolishly wants to go there). To the contrary many of the smokeless powders we use will not burn efficiently below a certain psi. If the firearm is capable of handling modern psi's then we can take any cartridge to that level given a cartridge with sufficient case capacity.

Certainly givve you an A+ for effort but the fact remains; The bottom psi end where any powder will burn efficiently is dependant on many things that are quite variable to the point that we can not reliable "chart" them. The top end of the psi range is not based on the burning rate of the powder as all can be taken "over the top".

Larry Gibson

[Wolfer]

Larry and Rocky,
My thoughts pretty much agree with both of you, of course I'm unable to write it quite as eloquently. My situation is that I'm shooting around 1700 fps with 2400 in four different rifles with excellent results but feel that I'm at about the end of 2400. I'm looking for the powder to take me to the next level. I have some 4895 that I'm going to try tomorrow but with previous experience feel that it might be a pretty good jump. I have some ramshot exterminator that I shoot in my 223 but have no data for it in much else. My experience has been that if it will work in the 223 it will probably work in the 30-30 with j-load but maybe not with boolits. For instance this 30-30 REALLY likes Varget with j-loads but with cast it looks like I'm shooting black powder. All this smoke tells me that the pressure is not high enough for this powder to burn right. My 100 yd groups would be better described as patterns.
I'm shooting a pretty soft alloy ( bhn 9/10 ) and am only looking for about 2000/2100 fps from my 30-06 and 8 mm Mauser and a little less in the 30-30. I realize that I may have to harden my boolits a bit but I like lots of expansion

[Rocky Raab]

I don't disagree, Larry. I was trying to give a parameter to judge the bottom end of the burning window. Certainly once pressures get above a powder's "happy place" it will continue to burn completely. Defining a powder's upper limit is not as easy.

For example, I have qualms about your statement implying that Unique is good for pressures up to 65Kpsi. Unique (and several other faster powders) exhibit a decided tendency to pressure-spike when taken above a certain level. That level may vary, but it can definitely be crossed. As you said about 3031, not all powders are good in all applications, and once the upper side of a powder's "window" is crossed, pressures can get very VERY erratic.

[Larry Gibson]

Rocky

Were in agreement, gave you an A+ for effort. I'm just pointing out the probable reason there is a "chart" for such......would be too many exceptions to make one really valid.

BTW; I didn't say Unique was "good for pressures up to 65K", just said it ould ignite easily and burn efficiently up to 65K psi. It certainly isn't a "good" (again we agree) powder for such as it is indeed to easy to "go a bridge too far". I have taken Unique to some pretty high psi (as far as I really cared to take it) and have measured the time/pressure curve. I've seen no indication of a "pressure-spike" but it appears there are different definitions floating around. What I found was a steady increase in the pressure until the max psi was reached. However, I did not graph out the rate of increase per additional powder increase so I can't say if the increase was linear or not. We do know that some slow burning ball powders rate of psi increase is not linear above certain psi's, usually higher than we really want to take them.

BTW; pressures are more commonly "very erratic" on the lower end where they are not burning efficiently. I could show you some pretty "scary" time/pressure graphs of low end .38 SPL target aloads and cowboy action loads....all factory BTW.

Larry Gibson

[felix]

Rocky
BTW; pressures are more commonly "very erratic" on the lower end where they are not burning efficiently. I could show you some pretty "scary" time/pressure graphs of low end .38 SPL target aloads and cowboy action loads....all factory BTW.
Larry Gibson


Corky and I played with the chrono the other day with 45acp's. We loaded some obsolete powders, starting "high" and working down. It was easily determined where the demarcation line was with each power and its various lots we had. We found a half-grain difference in three issues of Grey-B. Amazing. We adjusted each to an ES of 10, including an older power that Corky has a ton of. Velocities set to the minimum ES; velocities were from 820 to 890 with the lots we had using the Lee 225 quasi military lookalike. ... felix

[Rocky Raab]

I've never taken Unique a bridge too far with my own pressure gear, but I have seen some lab graphs that looked a lot like AlGore's infamous hockey stick graph. The cartridge was the 45 Colt, and that's why I personally shy away from Unique loads often quoted as "moderate" on a lot of websites.

Grey B, Felix? I've never even seen any!

[felix]

Grey-B appears to be a precursor to 231. The deterrent is unknown, and the powder is sand like rather than ball or smashed ball. Obtained from Hodgdon's back in the late 50's. ... felix

[felix]

Unique has always been spikey up and down its range of suitable loads using ACCURACY points. Just a half grain either way, for example using pistol sized cases in revolters, the accuracy changes dramatically. That's why various reports on the board suggest very specific charges for a specific application. I use 4756 which is more predictable by a LONG shot when Unique speed is called for. ... felix

[Rocky Raab]

Felix, I have always had to bite my lip and sit on my typing fingers when people praise Unique as more welcome invention than the front-snap bra. It's a good powder, sure, but it isn't fault-free. And you definitely can't spoon it in as though it were sugar.

[fryboy]

there are several powders that come to mind after 2400 runs out of steam so to speak , the two most stuck in my mind is what i would call semi cross-over powders 4198 and imr 3031 , others such as 4895 may certainly apply as crossover but not sure you could get the speed you seem after with it ( limited case capacity )

[frnkeore]

Something that I would like to see info on whether it be in pressure bomb, or say three different size case volumes (small, medium, large), is the pressure that it take to completely burn the different powders. I think that could be done and in my case give me something to work with. Upper limits are easy to find. If I had lower limits, I would have a starting point to find good loads on the target and chronograph.

There are so many powders out there today, that buying one of each to start load development for cast bullets is cost prohibiting.

Frank

[madsenshooter]

Larry and Rocky,
My thoughts pretty much agree with both of you, of course I'm unable to write it quite as eloquently. My situation is that I'm shooting around 1700 fps with 2400 in four different rifles with excellent results but feel that I'm at about the end of 2400. I'm looking for the powder to take me to the next level. I have some 4895 that I'm going to try tomorrow but with previous experience feel that it might be a pretty good jump. I have some ramshot exterminator that I shoot in my 223 but have no data for it in much else. My experience has been that if it will work in the 223 it will probably work in the 30-30 with j-load but maybe not with boolits. For instance this 30-30 REALLY likes Varget with j-loads but with cast it looks like I'm shooting black powder. All this smoke tells me that the pressure is not high enough for this powder to burn right. My 100 yd groups would be better described as patterns.
I'm shooting a pretty soft alloy ( bhn 9/10 ) and am only looking for about 2000/2100 fps from my 30-06 and 8 mm Mauser and a little less in the 30-30. I realize that I may have to harden my boolits a bit but I like lots of expansion

Wolfer, the area you're looking for is the realm of 4198, RE7, Lil Gun, etc, on up to AA2015, 3031 and Exterminator on the high end of those, but perhaps just what you're looking for. Wolfer, that's funny, my real name is Wolfe, R.

[Wolfer]

frnkoere
Yes, the lower end is what I would like to see. Like a lot of us I'm a poor boy and while there's a pretty good selection of powders on the shelf I would like to stock as few as needed.
Wolfe, R
Played around with the 06 today and learned a couple things
1- bhn of 9 can only be pushed to around 1700 in this gun. Much faster and you need a big target.
2- 4895 is too slow for this alloy at this speed.
3- 25 grs exterminator got me 1500 with good accuracy, 28 was better@ 1695', 30 grs needs a big target. I have some bhn 14 boolits drying now so I may be able to take them a little higher.

[Rocky Raab]

I have to laugh at "stock as few as needed." I've recently given away something like 24 cans of powder to get DOWN to 75 different kinds...

[btroj]

I don't look at things froma "stocking" point of view as much as I do a "what is best for this application" view. If I need a different powder I go and get it. These tend to be limited use powders for me, such as RE22 for my 270 Win using jacketed bulelts.

I do agree with Rocky that different powders have a pressure range where they seem to work best. This is why I use 2400 for cast only up to a certain velocity in 30-30 or 45-70 then change to a 4895 or Varget.

While looking at powders the way Rocky described them doesn't keep you entirely put of trouble it gives us an idea of what to expect a powder to work well for. Keep things in perspective and it sure is harder to get in trouble. Don't ask U ique to do the job of 2400 and you avoid lots of trouble.

[looseprojectile]

this thread started out with the OP wanting some indication of the powder to use to achieve normal pressure. Or pressure consistant with cartridge or and gun. Some manuals have pressures.
Nowhere have I seen anyone explain that if you keep "spooning in" powder and using faster powder, and increasing bullet weight the pressure keeps going up. Could exceed 65,000 psi easily.
There is no upper limit on any powder, as to pressure.
Some powders are slow enough that they will not create excessive pressures when loaded with the normal range of bullets and a case full of powder. Powders faster than that require more thought.
I was in a gun shop the other day and and the talk was about the Model 71/86 Winchester rifle that sold last week. An "86" with a "71" 348 barrel.
One guy kept calling it a 338. Just a little difference. Just load a 348 with a book load for a 338. It could be done. Seems like young inexperienced reloaders are in a race with old careless reloaders to destroy something. Don't happen often, thankfully.
Everyone should know that there is no pressure limit on any gun or cartridge.
Almost everyone does. A very few do not.
The pressure keeps going up as long as you keep increasing the resistance or tipping the can, however you do it.
You must start with with a loading manual and follow their formula. Please get the numbers right.

Life is good

[Rocky Raab]

LP, I think I know what you mean, but when you say "...there is no pressure limit on any gun or cartridge" it could be taken to mean that guns and cartridges are infinitely strong.

[Wolfer]

LP, I think I know what you mean, but when you say "...there is no pressure limit on any gun or cartridge" it could be taken to mean that guns and cartridges are infinitely strong.

Every thing has its limits! I've never found the ( pop off valve ) on a gun and hope I never do. I have stuck a few bolts and blown a few primers in my ( somewhat ) younger days but am more cautious in my old age!

[singleshot]

There IS an upper limit on how much pressure any propellant (smokeless powder) can produce. ALL OF THESE ARE WELL BEYOND THE LIMIT OF ANY FIREARM.

[looseprojectile]

My point exactly!!!!!!


Life is good