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Thread: powder question

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    Default powder question

    I have reloaded most of my life but pretty much keep things simple.. After reading another thread a question popped into my head that I thought about many times over the years.. First and formost I do not have any plans on attempting this just for the record.. Now the question.... What if there is no published data for a paticular powder how would you or could you simply use it based on its similar burn rate with other powders and if so where would you start as to not be below a minimum and get a hang fire...

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    You look at data for similar rounds using that powder and extrapolate a safe starting point . . . Or a new powder haveing little to no data you make the best guess you can by extrapolating everything you can find. There are also computer programs that will do it but I know nothing about them.
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    Great question, and one I'm working on too. My answer is lots and lots and lots of extrapolation from every single shred of data available. Hangfire is less a concern to me than blowing up or damaging a gun due to excessive pressure by any of the many ways such condition can be caused. To date, I've always been able to find some small shred of credible load data very similar to what I wanted to accomplish, with which to corroborate all my extrapolation and provide a starting point. Currently however, I can find no data at all from anyone who has used the powder I want to use, in the case I want to use it in. Treading very carefully, with a foundation of all the knowledge obtainable is my guiding rule. I won't have the new gun in hand for over a year tho, so I have time to think about it.
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    That pretty well sums it up, and it's as true for oddball wildcats as for odd powders in familiar calibers. As well as burn rate, I work off of case capacity and pressure range for similar bullet weights, but that's approximate. Within that realm I start at the low end of published data and work up.

    For example, I cobbled together a wildcat based on the 45-70 case blown out to minimum taper, then necked down to .429. The result is more case capacity than a 45-70 and a whole lot more than a 444 Marlin. I looked at data for 300 grain bullets in the (smaller) 45-70, then started with the bottom of those. The end result of working up from there was eventually beating the 45-70 by 150-200 fps and the 444 by somewhere between 300 and 400 fps with 300 grain bullets.

    Pressures still seemed relatively "mild" by looking at case expansion, primer condition, etc, but I backed off a fair bit since I didn't go the strain gauge route to confirm. Though mild pressure-wise compared to what some folks pound into the bolt face on their 45-70's, I'm getting similar velocities and a little boost in sectional density with lots less wear on guns and cases.

    Long and short of it, flights of fancy will lead you in weird (and sometimes expensive) directions with guns and powders, leaving you kind of holding the bag on loads and pressures. But common sense and thoughtful comparisons can help sort it out.

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    A big one not to be overlooked is to just call or email the powder companies. Most of the time you can get one of their ballisticians to provide you with load info. I would also review that against data for the same powder in a similar cartridge if possible just to make sure there isn't a gross error.

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    Well, Im cheap so I sometimes do things that most would consider a little off the charts. I have aquired from time to time powder and I do not know what it is. Most folks would use it for lawn fertilizer which is not a bad idea. I take an unknown powder and depending on its physical grain size I put 3 to 5grs in a 22H case with a 45gr cast boolit and fire it over a chrono. If it shows any signs of pressure I know I have a very fast powder. More than likely I will get low velocity and some unburned powder and I step the charge up a couple of grains and fire again. I continue with more powder until I get pressure or high velocity and I have a very good idea of burn rate. If I get a case full and still no pressure/velocity. I move up to a 223 case and about 15grs. Keep increasing powder until pressure or velocity gets high. Still no pressure/ velocity move up to a 308 case then a 270. Somewhere in this journey you will get pressure/ velocity and will have a fair idea of burn rate and can start low and work up in similar size cases. It's hardly worth the effort for a pound of powder but I picked up 24lbs of H116 and 25Lbs of what appeared to be 5010. I'm not throwing out 50# of powder so I needed to find a way to use it without scattering gun parts. The H116 is very close to Win 680 and in fact may be Win 680. The suspected 5010 probably is just that as it acts very close. If I have a cartridge with no data for a given powder I find a cartridge with similar capacity and bullet weight and start low and work up. I am not recommending any one else do this but it has worked well for me.

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    This'll keep you alive with all your parts intact:
    http://www.shootingsoftware.com/pressure.htm
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    Quote Originally Posted by Nitroman View Post
    This'll keep you alive with all your parts intact:
    http://www.shootingsoftware.com/pressure.htm
    Yeah, well, except that it only works with Microsoft...it may as well be powered by farm animals.
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    Well, that's a fine looking gizzy and it would probably help keep me from hurting myself with flying gun parts. However, if I were to bring that toy home and the wife found out how much it cost, I would be in a lot more danger than playing with unknown powders. I think I will pass on that.

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    Quote Originally Posted by Bear View Post
    I have reloaded most of my life but pretty much keep things simple.. After reading another thread a question popped into my head that I thought about many times over the years.. First and formost I do not have any plans on attempting this just for the record.. Now the question.... What if there is no published data for a paticular powder how would you or could you simply use it based on its similar burn rate with other powders and if so where would you start as to not be below a minimum and get a hang fire...
    Please read the post I made regarding the PressureTrace. If you want to start experimenting, or going where no others have gone before, you need to heed the advice.

    Quote Originally Posted by rbuck351 View Post
    Well, that's a fine looking gizzy and it would probably help keep me from hurting myself with flying gun parts. However, if I were to bring that toy home and the wife found out how much it cost, I would be in a lot more danger than playing with unknown powders. I think I will pass on that.
    How much would your hospital bill be to attach a severed finger after you blew it off experimenting with unlisted powders? I think the cost of the equipment and software would pay for itself many, many times over don't you? I don't bother with powders not listed, but I find it comes in handy so I am not guessing about loads. Besides, if you amortize it over five years then it isn't expensive at all. And you can learn so much about your loads too.
    Great spirits have always found violent opposition from mediocre minds. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence. Albert Einstein

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    A loading manual is not a receipe book and if you are handloading without a strain gage you are just guessing at pressures anyway. Probably 99+% of the people loading aren't using a strain gage so it's very little difference between what they do and what I do. We start low and build up looking for pressure signs because each gun will react differently to a given load. I have a 270Win that shows pressure a ways before the book says it should. Factory loads show pressure. Does this make a normal loading manual load ok? A strain gage is certainly better at reading absolute pressure than I. But I have been laoding for 45years and haven't scattered one yet. I also don't load to the very last fps. Many folks see what I do as very dangerous yet they will start at a max book load and think nothing of that. Many are loading the WSMs to sticky bolt lift and think that's ok and for that matter some factory loads are doing that in some guns. A strain gage may be the ultimate answer but it's not the only answer.
    I have been using duplex loads using the 5010 and a pistol powder to get pressure up to where the powder will at least burn relatively cleanly and this has worked very well for making low pressure loads for cast boolits in rifles. I wouldn't recommend this for everyone either but it works well if gone about correctly.

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    For those with strain gages, take a couple of powders that you currently use, one a fast powder like red dot or 231 and a slow powder say 4350 or H414, and use my proceedure along with your strain gage for safety to see if you can make a reasonable guess as to their burn rate. Only use your strain gage after using normal pressure sign readings and a chrono. If you start with a round like a 22H, use 3grs of any powder and a cast bullet. They do not make a powder that will hurt a hornet using 3grs. and a 45gr cast boolit. Check the primer the extraction, unburned powder in the barrel and the velocity. This will give you a very good idea of what just happened. Now check your strain gage and verify your guess. Move up to 4 or 5grs depending on what just happened and repeat. Using the fast powder you will run into high velocities and either filled out or flat primers before you run out of powder room. If you know nothing of pressure signs this is not for you. Reading normal pressure signs should tell you when to quit. Now repeat the proceedure with a slow powder. You will run out of case capacity before you get pressure signs so you move up in case size a little. Using your previous results load as if this is the fastest powder that could produce your previous results and continue until you get pressure/velocity. If the next case still doesn't produce pressure/velocity move up again until it does. Continue to verify your guesses with your strain gage and I think you will see you can do a very good job without the gage. If you are not good at reading pressure signs with velocity, this is not for you unless you have a strain gage. I am not the inventor of this system nor am I the only one doing this that still has all body parts intact. All that said it is still not for those with little or no experience reading pressure signs.

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    I little note from the strain gauge site:

    Note: If a barrel is not cylindrical at the chamber (where the gage is glued) the system MUST be calibrated against a load of known pressure. This is particularly true of double barrel shotguns with a strong flare near the locking mechanism, octagonal barrels, etc.

    Just how exactly is a guy supposed to calibrate his rifle with a known pressure load? I guess you can buy a box production ammo and shoot a few to get a theoritcal average but that's no positive guarantee of a pressure that you can use as a maximum.

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    Quote Originally Posted by marshall View Post
    I little note from the strain gauge site:

    Note: If a barrel is not cylindrical at the chamber (where the gage is glued) the system MUST be calibrated against a load of known pressure. This is particularly true of double barrel shotguns with a strong flare near the locking mechanism, octagonal barrels, etc.

    Just how exactly is a guy supposed to calibrate his rifle with a known pressure load? I guess you can buy a box production ammo and shoot a few to get a theoritcal average but that's no positive guarantee of a pressure that you can use as a maximum.
    Additionally, will any given load not produce a somewhat different pressure in different chambers due to variability of molecular structural characteristics and chamber dimensions?
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    Quote Originally Posted by iofthetaiga View Post
    Additionally, will any given load not produce a somewhat different pressure in different chambers due to variability of molecular structural characteristics and chamber dimensions?
    Actually no two identical loads, (as identical as we can make them) will produce the same pressure when fired in the same chamber/barrel. They never do I've read pressure on hundreds of thousands of rounds, we then average or take the mean pressure and put a dot in the middle of the mean curve and stay 10% below SAAMI peak average and call it good. We use standard deviation and exotic calculus and call it good.

    Calibrating the strain gauge can be a challenge but exact wall dimensions and type of steel/expansion characteristics must be determined.
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    I can only imagine the cost and the amount of equiptment it would take to get a real and accurate pressure reading from any given gun or cartridge. I can't believe a $750 gizmo is going to be spot on but probably more accurate than I can guess. A spent case with velocity can give you a pretty good idea of where to stop in a specific gun. Probably not as accurate as the gage but good enough. Using an unknown powder or loading for an unlisted cartridge is only a little different than using a book load in that you have to start much farther down to make sure you are starting below max. When you approach max the signs are the same. Still not for someone not familiar with powder burn rates and reading pressure signs/velocity but it can be done safely. I don't know when the ammo factories had accurate pressure machines but until then there was a lot of educated guessing happening.

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    I figured out a starting point for CFE 223 in a 325 WSM with 180's and 200's - nothing spectacular with accuracy but they were good loads - for what it's worth ....

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