Burn Rates of Smokeless powders

[Professor Marvel]

As the title says

Burn Rates of Smokeless powders

from IMR on the interweb:
this is from 2016, there is one from 2019 and perhaps a later version, which I will try to post later

I found it fascinating that Trail Boss burns faster than Unique...

[Coffinmaker]

  Harrumpff !! 

After all, when all is said and done, and the pudding is inna bowl, it becomes useless trivia.  Of no great material import.  So long as one picks one that works.

Besides.  I shoot APP.  Lots and lots of APP.  That Heathen Fad Smokeless Stuff is kind of passe in my lexicon.  Not at all interesting.  Smokeless requires careful measurement and selection to avoid nasty occurrences.  APP or BP on the other hand just requires you stuff the case.  Simple.  Elegant.  Effective.  With no muss, no fuss, just go out and SHOOT.  Besides.  TrailBoss SUX and you can't get it anymore (I don't think).  This missive hasn't contributed much to the original premise.  Sorry about that (no I'm not).  It's Sunday morning and I'm short on Caffeine and long on bored.  So if you've read this far, here ya are.  you must have been bored too!!  Nanny Nanny Poo Poo

Avoid People.  They be Hazardous to Yer Health 

[Professor Marvel]

Ah My Dear Coffin -
But I am all about measurement and charts and spreadsheets and various datum ad infinitum!
I have acquired, but have not yet used, my first velocipede velociraptor  chronograh ( not to be confused with
a timepiece).

If I can afford it I dearly want to get one of these newfangled PC based pressure measuring devices!
but I may need to find a new place to shoot first..

ikn the meantime I can examine the various data points betwixt "faster than " and "slower than" and correlate that
against the published veloicities and pressures of various loads m and then compare against some
results of prior experts in the field such as .44-40WCF ( Jack Christian) in his qwest to itemize and
quantify older loads....

cuz its fun

yhs
prof marbles

[Coffinmaker]

  My God Perfesser 

Ah yes.  THE FUN!!  That unquantifiable reason behind many endeavors.  Fun.  I was at one time very confused about that (fun, that is).  Spent many hours sitting at a bench with a 40 pound rifle, trying to shoot insanely fast bullets into a single hole at ranges I couldn't even see the black spot with the nekid eye.  Called it FUN.

Untold hours preparing the same 20 weight matched batch matched cartridge cases for precise loading and re-loading. FUN.

Then one unremarkable morning, I fired three rounds into one single hole.  A ragged hole, but yet a single hole.  After the euphoria wore off, I realized I had achieved the apex of my endeavor.  Nothing left to achieve.  No More FUN.  Oh Boo Hiss.

So.  The moral of the Story.  There isn't one.  It's Monday Morning.  I am returned from Mouse Safari.  I am bored, low on Caffeine  and my Armory resembles an indoor swimming pool so I am also some depressed.  No FUN.

Avoid People.  They be Hazardous to Yer Health (still)

[Virgil Lantey]

While I appreciated the burn rate link, I'm enjoying this conversation even more! Please continue.

[Bryan Austin]

Burn Rate is somewhat like having a V8 powered sports car that does 225mph. When the speed limit is 55mph, all powders are alike when loaded properly.

[Bunk Stagnerg]

I have been using this fad powder since the days of HiVel2 and FA#70 primers.
This reloading thing is very simple
                                                           USE THE MANUAL

In fact use a couple of different ones. just in case of a mis-print.
Burn rates are interesting I guess but they are NOT data. nor can data be safely calculated from them.
Loading data from Joey Baggadonuts will wind you up with a broken gun or serious injury or worse.
Gas hot enough to cut steel and at thousands of pounds of pressure is not something to be careless with.
Most likely the reason my powder of choice is real Black Gunpowder.
But at the end of the day it is your gun and your life so do what you think best and mention me in your will.
Respectfully
James Louis "Bunk" Stagner

[Professor Marvel]

Ah My Good Bunk

You and I are not only :"like minded" and  on the same page but are in the same choir.

Howver, like Bryan's efforts, this discussion is geared towards the advanced amatuer.

I do not have many pressure curves to work from ( thank you Bryan for posting your results!)
and there is occasionally  the issue of "too fast a pistol powder" in "too large a cartridge case"

One useful datum example is comparing Trail Boss and Unique.

Trail Boss ( as most of us know) was deliberately made as a fluffy powder to easily use in
large cases and reduce the risk of accidental double charges and there are a number of loads in
the manuals for it.

Some people came up with the erroneous idea that Trail boss is good for "older pistols".

In fact, Trail Boss has a faster burn rate and steeper pressure curve than Unique, making it ill suited
for weak designs or "older pistols",  Even tho the loading manuals show valid loads for both.

Thus both the "burn rate" and "pressure curve" data become useful

Of course one could always stuff a case full of APP but the  indoor ranges frown on it.

Then on a pratical note, since powder availability is "iffy" , I take my list of burn rates with me,
along with two of my favorite loading manuals when I wander down to the powder store.

There, I see what they actually have on hand, and I am using burn rates to determine which powders might be more
appropriate for short barreled pistols vs long barreled rifles, then go to the manual to determine appropriate published
loads and load data.

Often I find that what they have does not match what I want to do, thus saving time, money and grief.

On a esoteric philosophical note I am fascinated by comparing the burn rates and pressure curves
on several oldy moldy smokeless powders that a number of experts are using to good effect in
trapdoor, rolling block, and falling block rifles. One powder they like (I forget which) actually has a burn rate
and pressure curve datum that (according to their lab tests) closely match the original Dupont Best Rifle Powder.

yhs
prof marvel

[Coffinmaker]

  Perfesser-N-Others 

Let there be light!!  Yes!!  Flip the switch.  No !!  Wait!!  Having the knowledge of specific pressure curves can be highly evocative.  Er, of what he asks.  Well Now.

As pointed out by Monsieur Austin, I can in fact, drop a Small Block V8 into my Mini Cooper.  I won't be able to drive it, but I can get it in there (Actually been done) and that knowledge becomes totally useless trivia.  Is useless trivia.  Actually.

When, in my sordid, uneducated, heathen past, found myself in need to replenish my supplies is explosives (actually combustibles) for (combust really fast) furthering my penchant for playing with destructive devices and such, I found it best to simply peruse my available re-loading manuals to find a propellant I might like.  Sometimes that endeavor led me to some totally inappropriate selections anyway.  I mean sure, you can dump "X" amount of sifted Elk Snot into Y size cartridge case.  But what if you wind up with Kapouf rather than a satisfying BUUMBA??  Been know to happen.

There are other mitigating factors to consider as well.  Like a real serious FUN FACTOR!!  The kind of fun factor you get by ripping off a half dozen rounds full of 2F APP at an indoor range before they can get to ya!!  Superior fun you betcha.  All that satisfying coughing and sneezing from the stuck up snob glitterati is just marvelous.  And there is the screaming and tearing eyes, well you get the picture, as you calmly reload another half dozen .45 sized cartridges into yer hand howetzer.  And the poor schmuck at the counter is taking a dump in his (or her's) Post Toasties trying to stop you from setting off another batch.  Great FUN.

Oh, Where was I.  I know I had a point to all of this when I started, but be dam'd if I can remember what I wanted to say.  Obviously something of so little import I immediately forgot what it twer as it twer.  Oh well.  You've gotten this far so there is no going back.  Nanny Nanny Poo Poo.

Oh Wait!!  I remember!!

TRAIL BOSS SUX.

Remember, People still be Hazardous to Yer Health!!

[Trailrider]

BY ALL MEANS, USE THE RECOMMENDED LISTINGS IN THE LOADING HANDBOOKS! Over the sixty-plus years since I started handloading, I have found that if one seems to get close to or right on the maximum or minimum loads listed, it may be prudent to look at a different powder. Minimum loads in particular can present problems. It takes 5,000 - 7,000 psi (NOT CUP) to get smokeless powder burning stably. The listings in the manuals are determined under certain conditions which may not obtain in your particular gun, with a softer or harder cast bullet, or with too light a crimp. For example, if you want a reduced load in your .45LC, with bullets much lighter than 250 grains, rather than using Unique, you may be better served in going to W231/HP38 (same powder, different brand). If you have 2400, I definitely would not go with reduced loads, but with a faster powder, such as Unique.  In large magnum rifle cartridges, reduced loads of slow-burning powders can lead to real trouble! For example, DO NOT reduce loads for H4831 and others when trying to make a .338 Magnum feel like a light .30-06! Look at a faster powder such as IMR4350. These are generalizations, but as I shouted at the beginning, USE THE BLOODY MANUALS!

[Abilene]

All of my reloading is for CAS, and for that we need fast powders.  Since various powders are harder to find now, the burn rate chart is good to give an idea of what the faster powders are so as to keep an eye out for them when a preferred powder is not available.  Then use the load manuals for actual recipes.

[Professor Marvel]

Trailrider and Abilene hit the nail on the head. They have both gotten the point of this exercise.

The intent is NOT to hot rod anything , but in fact the very opposite, to safely
create safe, lighter low pressure loads in giant old fashioned cases.
BUT not mouse fart loads, either.

The burn rate and pressure curve data is most useful in that  effort.
AND for clarification, I am not talking about going below published minimums.

The most useful thing in this effort in my opinion, has been the availability of smaller cases such as the
.45 Schoffield and .45 Cowboy. I find that lighter loads are safer and more consistant in smaller cases.

I also feel there is not enough real data for consistancy - ie:
weather conditions, powder position, case length and volume, crimp...

Ah my good netizens, what about CRIMP? How does one actually measure crimp?
what exactly constitutes "light crimp, firm crimp, etc?

Aaaaand as Coffin said... I am bored.

[Bryan Austin]

Interestingly enough...to add to Trailrider's reply,

Unique was the powder used, a faster burning "rifle" powder than the W-A rifle powders of the day, for reduced 30cal military loads and service revolvers. Although Unique derived from shotgun powders-as most did-even then it was referred to as a rifle powder.

This has been a fun topic!

[greyhawk]

I like the burn rate charts
availability of powders for us (Aussies) is sketchy at best
USE THE BLOODY MANUAL ------yeah ok -----sometimes it aint in the manual

couple years ago I set out to load a 25/303 ---- a late model SMLE action rebarrelled properly - near new sportco barrel, neat chamber job, headspace is right.
Nothin in the books I have except for one old aussie manual listing powders that disappeared decades ago and I had 75 grain HP - they only started at at 87 grain
I had W760 powder (use it in my 22/250 an my 348W) and a bit of W748 leftover from loading a 30/30  I dont wanna go buy more powder just to fool around with this gun cuz once I get it worked out - its gonna sit in the corner till I send it away - Getting it sorted is fun but I really dont have a need for it.

In the more modern manuals I have data for 250 savage and the 257 Roberts -I figure my case capacity closer to the roberts but they dont list W760 for the 75 grain pill.
Back to the burn charts I can see where W760 sits in relation to what they list - etc - so I can figure a safe starting point (I know this powder well anyway but suppose I didnt?)   
Intelligent perusal of the manual will tell me that I can reduce down to a quiet load safely
so 3x 36 gr, 3x 37gr, 3x 38gr, no sign of pressure so go again 3x39, 3x40,3x41, still lookin ok 3x42 3x43 aint much room left here 3x43.5 and we got powder sittin about a millimeter under the base - rested on target looks good and the chrony sez 3250 FPS at 20 feet - load two more and the five shot group is about 2 1/4 inch at 100yards plenty good for what we might do. The brass looks good - nothin I can see that sez too much still we well over the older manual data for this particular round.

Besides all that reading the burn rate charts can be fun - who knew there were so many different versions of smokeyless powder ?   

[cpt dan blodgett]

I use burn rate charts primarily to find a similar powder to one I have been using and for what ever reason am either out of or cannot find to pick a substitute or want better perfomance or equal performance at a lower cost per round.  For instance when loading 155 grain to 175 grain bullets in a .308 the old gold standard was 4064.  Both Accurate 2520 and Hodgdon Varget are pretty close on the burn rate chart and are suitable powders for that purpose.  They are not equivalent powder and each will have its own max and min charges.  Varget also is less crunchy than IMR 4064