Burn Rate Chart

[snapshotmd]

I just found this chart on the IMR website.

So theoretically speaking, if I were to substitute a powder by selecting one that was close to it (within 1 or 2), and there was no loading data readily available for your cartridge, would the powder weight be more or less similar?

For example, if I were loading for 357mag and there was no Winchester 296 available, can I substitute with IMR 4227 and start out with the minimum recommended load for Winchester 296?

 

[Mud Turtle]

Although I have been handloading for pistols, rifles, and shotguns for alot of years, I am no expert. I would never substitute a powder for another just based on burn rate. I want to see the load in a reputable manual or from an acceptable source. I would assume nothing. If there was no data for it, I would use another powder. I would be overly cautious. Just my 2 cents.

 

[GNLaFrance]

I'm with Mud Turtle, use only published load data. This is what my reading tells me to say:

If you absolutely must try another powder, please start out 15% below the minimum recommended load for the one you're substituting it for, and increase it no more than 3% at a time.

Check for increased noise and recoil, case and primer indications or anything else that tells you you're approaching high pressure levels. If you see any sign of it, back off and stop 1 or 2 steps below that level.

I am not an expert, much less a daredevil, and perhaps that is why I still have two eyes and ten fingers.

 

[JRSpicer426]

Pistols I cant speak for, Rifles its prob ok but can be unique because its not just burn rates (linear), its burn rates at specific pressures levels. ie, you could get a "runaway reaction"

Shotguns stay the hell away from. There is no adequate way to check for overpressure until its too late-

 

[j8064]

Even though I've been a reloader for over 20 years, I'm not an expert either. I totally agree with what Mud Turtle and GNLafrance said. Stick with published load data from reliable and reputable sources. Substituting a propellant 'because it's close' for one that has actually been tested and the data published is just not a good idea.

Generally reloading manuals and powder manufacturer's websites list a variety of powders tested for different cartridge and bullet weight combinations. Personally I'd feel a lot safer following those guidelines than 'guessing' a powder that's not been tested is maybe close so therefore should work fine.

To me that ranks up there with, "Hey, hold my beer and watch this".

 

[Biggfoot44]

Burninng rate has no connection to safe charge wt. ( ok, it is one of a bunch of factors, but in a single variabble comparison it's all over the map).

 

[Mdphotographer]

All that chart shows you is their RANKING of burn rate from lowest to highest NOT which powders burn AT the same rates.I load .30-06 for the Garand and .223 for AR and the loading similarity between Varget and IMR 4895 are very close according to the loading data books but on that chart they are pretty widely spaced in the listing.If you had a chart that showed which powders burned within a specific rate then you could work up loads with that data.Using that chart could lead to a disaster as you don't know how big a difference between one powder and the other is,they could be very close or they could be a big spread even if they are ranked close together.

 

[GNLaFrance]

This book has made what actually happens when you burn powder more clear to me than anything I've read before. I'm re-reading it now. Modern Reloading Second Edition by Richard Lee <$14.00 from MidwayUSA, $30.00 everywhere else.

 

[Capt.Link.]

They do make some software I think RCBS and others that take into account many of the variables and you must be super careful about light charges with magnum powders a under filled case is a bomb

 

[bulletbill]

They do make some software I think RCBS and others that take into account many of the variables and you must be super careful about light charges with magnum powders a under filled case is a bomb

Yeah that secondary detonation is a bitch...

OP: If you're looking for a comparison chart this is about the most complete I've seen so far..

Burn Chart

 

[snapshotmd]

That's a really good chart. Thanks! So I take it that the powders on the same line as the one you're substituting are about the same charging weight? Probably a good idea to start 15% less of suggested starting to be sure.

 

[Capt.Link.]

Read my above reply starting to low with some powders will blow your head off and yes I am trying to scare you.Read the load in a book and do not go below the recommended charge if you wish to play get one of the programs and if you don't have it the Lyman Reloading book and the ABCs of reloading its your head

 

[bulletbill]

Yeah, I wouldn't use the same charge based on burn rate. Burn rate doesn't correlate to potential energy. Wild catters would compare similar burn rate powders across numerous cartridges then determine what *might* be a safe charge and work from there. They would also consult the powder manufacturer for suggestions.

*Edit* The *same* powder from different lots may not even be the same charge weight, just an FYI. Is possible that the formula gets updated and you buy one pound now, one pound in another month and those two may have different charge weights. Always consult the manufacturer, even if what you're looking for isn't published. All burn rate charts state is these powders *may* perform similarly.

 

[CKOD]

If you want to start working up your own load, I'd check out quickload software. Rather then just being an index of loads, it will actually calculate pressure vs time for different powders, bullets and cartriges.

Its $90 I believe, but if youre going to be playing around like that, then I'd say its worth it to be better informed.

 

[alucard0822]

A good example of why you do not want to substitute load data for other powders is H4895 vs IMR 4895, look at the load vs pressure for those two, even though they are right next to each other in the chart, and almost have the same name, they burn completely different.