Powder Load Conversions for the experienced

[daddyseal]

Beginners Should NEVER Do This~!!!

Before I get slammed by folks saying to follow my manual's listed loads for Only the powders and loads listed,
I want to say that I've done this successfully a number of times.
So, I'm wondering about others here having done it also.

Basically, if the is no load data listed for a certain powder for my boolit weight, shape, type and composition, but there is a load given for a number of other powders.
I look for data for the same caliber, type, shape and composition, but a slightly different weight, which shows a load for my powder and a powder listed for the boolit that I'm reloading.

Do other reloaders here do that too to get loads for a powder that want to use, but is not listed for the weight boolit there are using?

[drklynoon]

I try other reloading manuals. Or I go to the sight of the powder manufacturer/ distributor. If the load is for a high pressure cartridge I do not guess. If it is a low pressure large volume I have on occasion deviated to a starting load from another boolit type. Fast burning powders in small capacity cases can get REALLLLLLLY hairy. If a specific powder is not recommended in any reloading manual for the boolit weight you are working with there is probably a reason.

[drklynoon]

P.S. Hodgdon shows the load for a 150 gr .40 S&W at 3.8 starting to 4.0 max for a max speed of 960 FPS. This is the lowest speed of any powder listed on the Hodgdon sight for this weight of bullet. It is also tied for the lowest pressure. Here is the reason against guessing for powder weight: At certain pressures some powders become extremely violent. They no longer burn, they explode. This pressure s not always consistent as case capacity is a factor as well as other things. My advice is that when loading for 40's or 9mm or other low capacity high pressure rounds you need to find data that corresponds to your bullet weight. If it is not found than try another powder. Bad things can happen even in a low pressure application and when the powder is only listed with a .2 gr split it illustrates how touchy loading is.

[jdgabbard]

Sounds to me like you're playing russian roullet with your fingers/hands, face and life.

[Bwana]

"At certain pressures some powders become extremely violent. They no longer burn, they explode."

Not true. Progressive powder does not "explode". It's burn rate may become faster than the bullet/boolit movement can accomodate; but, that is different than "exploding".

[drklynoon]

Bwana, You are correct in saying that it doesn't explode. However, the result from an over pressured powder becomes violent enough to possibly rupture the case or the firearm. For all intents and purposes I believed that a simpler explanation would be more apt for a poster who was asking this type of question. Maybe I was wrong in assuming this but I did not think it was necessary to attempt to explain in that type of detail. I figured "explode" would get the point across. I have found that when trying to explain something it becomes increasingly difficult to tailor the information to the person asking the question in a way that does not mislead them. You are correct sir, the type of powder in which we are using does not "explode" it does burn and I thank you for pointing out my error. SealDaddy, I hope this helps you in some way.

[nhrifle]

I try not to experiment too much with small pistol cases, since there is such a small window between a safe load and one that's dangerously over pressure. I don't have pressure barrels and load cells at my disposal, so I load for pistols a bit more cautiously than rifles. I have experimented with rifle cases extensively though. As long as one uses good loading practice and sane extrapolation of existing data, new and safe load combinations can be found.

[asp]

Anytime I go into uncharted territory, I start with a load that I know will be very light and slowly (.1 or .2 gr increments, depeding on the load) work my way up while watching for pressure signs or fall off on accuracy, whichever comes first. I'd like to add a chronograph to the process, but not yet. I think of it like a science experiment. How do you think the manuals came up with their published loads in the first place?

FWIW most of my load development has been on larger cases. I haven't gotten to .40 yet (despite having all of the tooling for it)

[drklynoon]

After you changed the example to true blue I looked at ramshot's website. They list the starting load for a 155 gr boolit at 6.5 gr and max at 7.2. I would weigh your bullet and if the weight is close within in 3-5 gr. I would use the load data supplied by ramshot. If my guess is correct the load you suggest would be over pressure. This is the danger in not using published loads. Published loads are developed in a pressure barrel in a controlled environment.

[daddyseal]

P.S. Hodgdon shows the load for a 150 gr .40 S&W at 3.8 starting to 4.0 max for a max speed of 960 FPS. This is the lowest speed of any powder listed on the Hodgdon sight for this weight of bullet. It is also tied for the lowest pressure. Here is the reason against guessing for powder weight: At certain pressures some powders become extremely violent. They no longer burn, they explode. This pressure s not always consistent as case capacity is a factor as well as other things. My advice is that when loading for 40's or 9mm or other low capacity high pressure rounds you need to find data that corresponds to your bullet weight. If it is not found than try another powder. Bad things can happen even in a low pressure application and when the powder is only listed with a .2 gr split it illustrates how touchy loading is.

Odd...you didn't specify shape or lead composition,... but my new Lyman's cast bullet handbook #4 shows load for Unique to 5.0 min and 6.3 max. Why the bid difference?

[daddyseal]

Anytime I go into uncharted territory, I start with a load that I know will be very light and slowly (.1 or .2 gr increments, depeding on the load) work my way up while watching for pressure signs or fall off on accuracy, whichever comes first. I'd like to add a chronograph to the process, but not yet. I think of it like a science experiment. How do you think the manuals came up with their published loads in the first place?

FWIW most of my load development has been on larger cases. I haven't gotten to .40 yet (despite having all of the tooling for it)

Exactly, friend~

[drklynoon]

The information from the Hodgdon site is for a 150gr JHP. In lieu of a specific cast load a jacketed load can be used safely. The differences are more than likely due to lead v. jacketed; however, I have found many variances from one manual to another. This is were your experience comes into play.

[drklynoon]

The data from Ramshot is for a cast boolit RN SWC.

[daddyseal]

The information from the Hodgdon site is for a 150gr JHP. In lieu of a specific cast load a jacketed load can be used safely. The differences are more than likely due to lead v. jacketed; however, I have found many variances from one manual to another. This is were your experience comes into play.

I have 5 manuals and I too have seen minor differences, but only minor.

[Larry Gibson]

daddyseal

That is one way to go about interpolation of finding a powder charge when using an unkown powder. Is it safe? If one definately starts low and works up in the traditional manner it is.......relatively as reloading always has a certain "risk" to it. How much the risk is depends on one's level of experience but even experience reloaders can easily get into trouble.

I suggest if one is going to "interpolate" as you mention that one also use a reliable "burning rate chart". By selecting a powder with loads listed (same type and composition) that is within 3 posititions on the chart faster burning then those loads should be safe with the slower burning powder you are interpolating for. Of course I will again say that the loads should be worked up n the traditional manner by an experienced reloader who understands psi signs and uses a chronograph correctly. I would definately not recommend this method for selecting "a" load to use as many want these days using the "internet shortcut method".

Larry Gibson

[williamwaco]

I to extrapolate loads from published information for other cartridges, powders, bullets.

I would not describe my methods.

Any one who has enough experience can figure it out for himself.
Any one who doesn't should not be following someone else's method.

.

[daddyseal]

daddyseal

That is one way to go about interpolation of finding a powder charge when using an unkown powder. Is it safe? If one definately starts low and works up in the traditional manner it is.......relatively as reloading always has a certain "risk" to it. How much the risk is depends on one's level of experience but even experience reloaders can easily get into trouble.

I suggest if one is going to "interpolate" as you mention that one also use a reliable "burning rate chart". By selecting a powder with loads listed (same type and composition) that is within 3 posititions on the chart faster burning then those loads should be safe with the slower burning powder you are interpolating for. Of course I will again say that the loads should be worked up n the traditional manner by an experienced reloader who understands psi signs and uses a chronograph correctly. I would definately not recommend this method for selecting "a" load to use as many want these days using the "internet shortcut method".

Larry Gibson

Right...that's why I listed the minimums, I start there and test...then work up 0.1 at a time.

[mdi]

One thing to remember is powder charges/burning rates are not linear/consistant. Pressure is a major factor, so a charge difference of xx.xx grains between ABC powder and XYZ powder at say 20,000 PSI won't be the same diference/ratio at 30,000 PSI or even 12,000 PSI.

[daddyseal]

One thing to remember is powder charges/burning rates are not linear/consistant. Pressure is a major factor, so a charge difference of xx.xx grains between ABC powder and XYZ powder at say 20,00 PSI won't be the same diference/ratio at 30,00 PSI or even 12,00 PSI.
Right, I know that.
Thanks for your input, friend~!

[mpmarty]

Of all the cartridges available the last one I'd feel comfortable guestimating loads for is the .40 S&W it is already critical and has a bad history of mishaps.

[daddyseal]

Of all the cartridges available the last one I'd feel comfortable guestimating loads for is the .40 S&W it is already critical and has a bad history of mishaps.

OK, thanks.... 44 mag?

[drklynoon]

Using your extrapolations in the example this load "7.8 gr. true blue" is 12% over ramshot's maximum load for a cast 155 gr. bullet. I believe that 44 man was trying to simplify the answer to your post and should not be overlooked. I do not have the experience level of some on this board but have been reloading for a decade and have been around it for the better part of my life, that being said I can not imagine an "experienced" reloader giving advice about how to extrapolate powder charges as you suggest for cartridges such as 9mm and .40 S&W. As was mentioned earlier powder burn rates are not linear and often spike at certain pressures and this becomes increasingly more difficult to guess at when capacities are as small as they are for these cartridges. I am sure this is not the answer you were looking for and I apologize for that. Find the closest reloading data you can before you make any extrapolations. I know that money can be tight and many do not have 30 reloading manuals to check but many resources are available on line through Hodgdon, Alliant, Ramshot and others.

[Cherokee]

daddyseal - I understand what you are saying. Like you & williamwaco, I have extrapolated beginnng loads from published data in the past. I like the way willian said it in post #16. I try to avoid it.

[daddyseal]

Using your extrapolations in the example this load "7.8 gr. true blue" is 12% over ramshot's maximum load for a cast 155 gr. bullet. I believe that 44 man was trying to simplify the answer to your post and should not be overlooked. I do not have the experience level of some on this board but have been reloading for a decade and have been around it for the better part of my life, that being said I can not imagine an "experienced" reloader giving advice about how to extrapolate powder charges as you suggest for cartridges such as 9mm and .40 S&W. As was mentioned earlier powder burn rates are not linear and often spike at certain pressures and this becomes increasingly more difficult to guess at when capacities are as small as they are for these cartridges. I am sure this is not the answer you were looking for and I apologize for that. Find the closest reloading data you can before you make any extrapolations. I know that money can be tight and many do not have 30 reloading manuals to check but many resources are available on line through Hodgdon, Alliant, Ramshot and others.

You've got me there!
I should never have used True Blue as an example. I should have done it with Unique and Universal.
Thanks~

[MT Gianni]

daddyseal - I understand what you are saying. Like you & williamwaco, I have extrapolated beginnng loads from published data in the past. I like the way willian said it in post #16. I try to avoid it.

Extrapolation is drawing from unknown sources to make a solution. In other words, Unique shows a starting charge of 5 gr therefore 5 gr works in any cartridge or with any powder. Extrapolating any data is fraught with mistakes. Interpolation is that 5 gr of powder X produce 500 fps, 10 gr of the same powder produce 1000 fps, so 7 gr should produce 700 fps. You may think that a similar burn rate powder will produce the same but should always begin with the starting loads.

[Mooseman]

I must laugh when I hear powders "Dont Explode"..because neither does most commercial explosives, They Burn FAST ! Granted they burn faster than reloading powders but the object is the same , to produce huge amounts of pressure to use for a purpose.When a gun is fired it is a controlled explosion hence the boom. Without the proper equipment to measure pressures and if you arent a powder engineer you are playing with fire when you use unproven data. I use explosives for mining , etc ,and been loading ammo for 40 years and I still wont experiment with a bomb in my hand...

[dromia]

Extrapolate at your peril, and worse still at the peril of others.

If it was that simple then there wouldn't be the need for all the data out there.

Getting away with it a few or even many times is no recommendation of safety.

[rbuck351]

I do that to some degree but I definately start low. If I don't have data for a 150gr lead bullet but do have data for a 175gr, I would start at the starting load for the 175 and work up from there. Dropping bullet weight for a given powder/bullet is not likely to cause any problem. Then using a chrono work up until either velocity or pressure show it's time to stop. It just doesn't take long or a lot of components to start plenty low and work up. I would not recommend this for beginning loaders.

[Larry Gibson]

"Extrapolation" can be dangerous if misued, that is well understood. But done correctly by the experienced it is probably as safe as "working up a load". Many experienced reloaders have been "extrapolating" quite safely with milsurp powders, new powders and in developing loads for wildcats. Besides, what do we think the manual ballisticians do with new powders in old cartridges, old powders in new cartridges or new powders in new cartridges? Where does ther "data" come from since they are the ones developing the "developed data"? Where do they come up with starting loads for such? They "interpolate and extrapolate" the starting loads using known data of similar burning rates and types of powder and then test the loads. Granted they have more sophisticated equipment than most of us but the technique is the same and the risk/danger the same. They are quite successful at such "extrapolation/interpolation" and so can the experienced reloader be.

Larry Gibson

[daddyseal]

"Extrapolation" can be dangerous if misued, that is well understood. But done correctly by the experienced it is probably as safe as "working up a load". Many experienced reloaders have been "extrapolating" quite safely with milsurp powders, new powders and in developing loads for wildcats. Besides, what do we think the manual ballisticians do with new powders in old cartridges, old powders in new cartridges or new powders in new cartridges? Where does ther "data" come from since they are the ones developing developing the data? Where do they come up with starting loads for such? They "interpolate and extrapolate" the starting loads using known data of similar burning rates and types of powder and then test the loads. Granted they have more sophisticated equipment than most of us but the technique is the same and the risk/danger the same. They are quite successful at such "extrapolation/interpolation" and so can the experienced reloader be.

Larry Gibson

Right, friend....And Definitely NOT something a beginning reloader should attempt, we all agree with that~

[HABCAN]

Larry Gibson, your Post #29, Sir: I second your opinion completely. I DO have drklynoon's 30 reloading manuals (how did you know?) and have been at the game since 1947................the advice posted about using a reliable burn-rate chart is good.............but check with more than one! And as for 'experienced handloaders'.......forty years of only following manual recipes makes an 'experienced assembler', not 'handloader'. Carry on smiling..........and interpolating! A person is only responsible for his own actions.

[Wayne Smith]

For pistol ammo I am an assembler! Proud of it. Not much room to play with those cases and I want to keep my guns. With rifles, if I have an odd size (wt) boolit and not a lot of data I will extrapolate, but only if I have data for a larger boolit and a smaller one for that powder. Yeah, I play it safe. I like my guns and my limbs.

[daddyseal]

For pistol ammo I am an assembler! Proud of it. Not much room to play with those cases and I want to keep my guns. With rifles, if I have an odd size (wt) boolit and not a lot of data I will extrapolate, but only if I have data for a larger boolit and a smaller one for that powder. Yeah, I play it safe. I like my guns and my limbs.

And Eyes...lol
Thank you, I am Very careful, friend~!

[DrCaveman]

You might try to find one of those little "all-one-caliber" paperbacks dealing with either of those cartridges. I bought one for 357 mag also for 30-06 and it brought a lot of loads to the table that I hadn't found elsewhere.

Even more useful for what you're trying, I found the coverage of powders to be quite impressive, since they compile data from powder makers, bullet makers, mold makers. I was able to find very close parallels to loads I was contemplating. Having at least 2 or 3 components match a printed recipe is comforting. To me.

[daddyseal]

You might try to find one of those little "all-one-caliber" paperbacks dealing with either of those cartridges. I bought one for 357 mag also for 30-06 and it brought a lot of loads to the table that I hadn't found elsewhere.
Even more useful for what you're trying, I found the coverage of powders to be quite impressive, since they compile data from powder makers, bullet makers, mold makers. I was able to find very close parallels to loads I was contemplating. Having at least 2 or 3 components match a printed recipe is comforting. To me.

Very Good~!!!
I Definitely Will Ge One To See That.
Thank you, friend~