Can burn rate be used to create unpublished loads?

Be safe! Don't create new loads. Use powder mfg load data.

You do not want to be the Darwin Award winner of the week

Burn rate is only ONE factor in a powder's ballistic response:

- Burn Rate/sec
- Energy content (Heat/Kg)
- Ratio of specific heats (specific heat at constant pressure vs and the specific heat at constant volume)
- Progressive (or de-gressive) burning rate (with increasing pressure)
- Progressive burning limit (at which point it quits increasing pressure)
- ...and last but not least: a "Factor b" to balance the thermodynamics

As you can see, don't EVER use simple Burn Rate to estimate loading results.

Pressure and volume is part of the "explosion" equation of powders. Some powders coatings and buffers are designed to burn at a certain pressure and case volume. On either side of those parameters and boom goes the dynamite.

Sorry MEHavey...I wrote while you posted.

I'm in the same boat, but I bought 6 lbs of N32C. So far it seems like a great powder.

Luckily for me, Quickload has N32C in it. This gives a general idea of what the powder will do under the prescribed circumstances. I haven't done it yet, but I will start low and work up, using a chronograph to see to what degree the data matches the real world. And stop early. I'm not looking to use this powder for anything other than very low pressure target rounds for use in stout, modern guns.

I would like to caution that although N32C is similar to Trailboss, from playing around with Quickload it appears that you CAN put too much powder in the larger cases and cause an overpressure situation. Again, this is all a simulation, but the number calculate that way.

As the others have said, this is an advanced handloading project, and I think I'm ready to proceed. Do NOT try this, if you're a beginner.

-John

back in the naval war of ww1 and ww2 the british discovered something peculiar about their cordite powder charges for naval guns using seperate powder charge and seperate projectile.
the big 100 pound bag of cordite would simply burn and act like a big harmless roman candle. but if any kind of force was applied, so much as say a door swung shut on it, KABOOM.
Thats the problem with trying to make your own load tables by "matching burn rate".

Whether or not you use minimal loads has little to do with what may happen by developing data that simply doesn't exist. If it were within the range of the powder and cartridge concerned, I'm sure the manufacturer would have published it. Don't do it, powders can produce very unexpected pressure results when applied to the wrong cartridges.

GS

If you have to ask, then you are not experienced enough to try.

Loads are published, because they are TESTED with Equipment that we don't have.
Not all powders are listed, because some are tested and POOR performers, and others are just Dangerous.
Stick with published Data, at least for your perameters.
But if you want to play with Untested loads ?
Then ask yourself, " How much is my Gun worth, and what Body part do I not need ?"
Then do your own experimentation.

You can get away with it in .38 Special and other non-magnum revolver cartridges, but I don't recommend it. (if you knew enough to do it, you wouldn't be asking, no offense intended) Don't even think about it in 9mm and .40S&W.

People have worked up loads with less. There's really no foolproof recipe for doing so, though.

Why not contact Vihta Vuori? Maybe they'll say that they tried it but deemed it too dangerous for what you want to use it for.

W/ a burn rate chart alone, no. W/ a burn rate chart and chronograph, yes. Even better is Quickload and a chronograph. None of this is for a novice reloader. But people have developed loads for unknown powders over the years. You just have to approach it in the proper fashion. Just want to point out again that this isn't for a novice reloader.

You don't want to try it without a chrono. And you don't want to trust a single burn rate chart, because many of them vary depending on the source.

If you get several charts, and you can verify a consistent "zone" that a powder falls into, then you can attempt to work up a load in a cartridge that similar powders work for. Pick a relatively safe and moderate target velocity that you want to achieve - I'd never try to work up anything "hot" with such a powder.

Then, you want to start quite low on the charges. I always start well short of what I think will even cycle the action. Do 5 rounds each at increasing intervals of 0.1gr (maybe 0.2gr). Take those out to the range, and start with the lowest powder charges first and run them over the chrono. Record your data. Keep using the next charge up until your average velocity reaches your target goal and the action is consistently cycling (or if for a revolver, just get to your velocity).

At that point record your desired charge. Take home everything above that and pull the bullets immediately, sorting out the components for reuse (I generally don't reuse pulled powder, even if I know what it is, but I'll reuse everything else).

As noted though, this isn't really a beginner activity. Unless you're very familiar with loading and have been doing it for several years, I wouldn't recommend it.

mgmorden said:

As noted though, this isn't really a beginner activity. Unless you're very familiar with loading and have been doing it for several years, I wouldn't recommend it.

Click to expand...

Why are guy’s always saying this isn't for the beginner? I have been reloading for 30 years so does that make me qualified to make my own loads? From your description of looking at burn rate charts and shooting over a chrony why would it matter if the reloader has been loading for a month or 50 years?

To the OP. What you are asking about is a very risky deal, sure it can be done and has been done for years. The above posts on how to do it are about the only way for the home hand loader to do this as we don't have access to proper test barrels and other testing devices. As you have seen you are going to get a ton of posts from the just follow the published data crowed and the your going to die crowed which is to be expected when one asks a question that involves things that go boom. In the end you have to decide for yourself just how much risk you are willing to take.

Pressure curves are very different between powders with similar burn rates. One loaded 25% over max may give you pressure signs and the other may wreck your gun. You may be able to guesstimate a starting load and very carefully work up or you may not.

Without pressure testing equipment, the chrono etc. are still just guessing.

LET IT BE NOTED : The burn rate chart is as BEST a highly edjumacated GUESS. Every propellent in it changes places with others in different calibers, different primers, different guns, different pressure guns etc et ec etc etc etc.........................ETC
YOU are being foolish if you think you can out guess it, or predict from it, or use it in any other way excepting that for which it is formulated. WE COULD NOT DO IT IN THE BALLISTICS LAB, so what in the flying hades makes you think you can do it with a cheap chronograph ?
And so it goes...

The Vihtavuori 11th Edition Reloading Guide has publishes Cowboy Loads with N32C in .38 Spl, .357 Mag, .44 Spl, .44 Mag, and .45 Colt. OP, what specifically are you looking for?

http://www.lapua.com/upload/downloads/brochures/2013/vihtavuori_reloading_guide_ed11_2013eng.pdf

I just looked up some potential "unpublished" TIN STAR loads using QuickLoad.

I would NOT play with this powder without firing some published near-top end "cowboy" loads to get the results calibrated in that ballistics software's powder variables... and then working veeeery carefully from that point with a good chronograph and QuickLoad pressure/velocity predictions right next to me.

Otherwise.... (the immortal words of Marcel Marceau seen/heard HERE.)

The problem with using burn rate is that you don't know how much different one powder is from another.

For instance:

14. Hodgdon Titegroup
15. Alliant American Select
16. Accurate Arms Solo 1000

Now how much difference is there between 14 & 15?
Is it the same amount as in 15 & 16?

To make a long post much shorter, just don't.
It isn't worth the price of your gun, or your hand or your face, etc, etc.

I'll try almost anything once and I've been known to experiment with hot loads, but only as an extension of published load data. I'd be reluctant to experiment with a cartridge for which there is no published data to use as a reference.

But if I did, I would absolutely need to know what kind of pressure I was dealing with. Even for a bolt action.