Smokeless Powder Burn Rate Chart

[Kurz]

The Forum Boss posted the newest version of the Hodgdon/IMR burn rate chart on the Bulletin. It's an excellent example of useful information for all reloaders. Print it out, download it as it is easy to use.

I reload a lot as do many of the builders I know. So we are constantly looking for more and better information and data to help us in our work. This is a good example.

However, lot-to-lot variations often call for an amended view of the same information, so I have a version which can be reorganized as the changes are called for. These are kept in file also, so that we can track and check our data and not lose the important original.

While searching out some additional information, I ran across this version of a slightly larger burn rate chart:

Use it for comparison since there can always be a slight amount of dissimilarity between authors. None of these are fixed in stone, especially considering the variations in lots. It's all good information to help us be better reloaders.

Here is the newest rendition from 2020 for comparison:

 

[wiguy]

Yes, many of us have our old standbys, new powders coming out often though. I recently bought 9 lbs if IMR 8208, lots of good reviews. Most of what I load for calls for rates in the TAC/4895 to just a tad slower range, Varget to 4350.

 

[Ccrider]

Thanks. Nice to sort of compare. Noticed no Reloader 16, T 30 or T 32.

 

[Kurz]

Rarely if ever have I found T30, T32 on a burn rate chart. I've always had to interpolate found loads with the case I'm thinking of using with those two powders. It's a nuisance but it gets me close.

 

[Bc'z]

Also no IMR4166, RL26 just from a glance

 

[Kurz]

There are foibles for each version. The Hodgdon/IMR in the Bulletin has Re-26.

 

[Nature Boy]

These lists seem to lack proportionality between powders. In other words, you could have two powders five or six positions apart from each other but be closer in burn rate than two other powders in a different place on the list that are only two or three spots apart.

Has anyone ever seen this list shown in a graph or plot that takes the proportional factor into account?

 

[BenPerfected]

How is the powder burn rate related to accuracy?
Ben

 

[338 dude]

Thanks. Nice to sort of compare. Noticed no Reloader 16, T 30 or T 32.

Also missing reloader 23 and 26

 

[Kurz]

Yes and so is Re-33. According to Alliant, they are not releasing the closed bomb data to anyone, it's being kept inhouse only. So call Alliant and ask them to supply the data so we can update the charts.

 

[MagnumManiac]

Funny thing, burn rate charts are so far from the truth as to actual rates between manufacturers that they are simply a rough guess at best.
RQ (relative quickness) numbers between manufacturers are NOT set to any given STANDARD.
So IMR May give 4895 a RQ number of 100, then all other powders faster are given lower numbers and all other powders slower are given higher numbers.
Then Hodgdon gives 4198 a RQ number of 100 and the same happens as above, then a list is made by HOW the manufacturer states THEIR burn rates in order of RQ numbers, which are not relative to anyone else’s burn rates but ends up on a burn rate chart.
The other problem is that burn rates are not constant and change as case shape/size/bore ratio changes as well.

Cheers.

 

[Ggmac]

How is the powder burn rate related to accuracy?
Ben

It's not

 

[MN50Shooter]

Bottom Chart omitted Alliant Reloader 50. I wonder why?

 

[BenPerfected]

It's not

What if anything is important about the powder burn rate?

 

[tominboise]

Powders with similar burn rates "should" perform similarly in the same cartridges, so it allows one to make semi educated guesses about the best powders to start with, when reloading and looking at what one might have in the cabinet.

 

[Ggmac]

What if anything is important about the powder burn rate?

Burn rate is important but along with it is density, actually just as important . They can be similar in burn rate but one could weigh considerably more than the other next to it in burn rate or it could fill a greater volume . Same but different.

 

[Dnchrist1]

Burn rate is important but along with it is density, actually just as important . They can be similar in burn rate but one could weigh considerably more than the other next to it in burn rate or it could fill a greater volume . Same but different.

If the burn rate is too fast in AR15s, for example, it results in stuck cases, because they try to eject before they are ready.

 

[ebb]

The last one I saw did not have superformance, with it right next to H4381 it opens all kinds of possibilities for me. 25-06 6.5-284

 

[CJ6]

No Shooters World/Lovex powders listed either.

 

[jackieschmidt]

How is the powder burn rate related to accuracy?
Ben

Good question.
in many cases, a powder that gives as close to a 100% fill while achieving the desired velocity will also often be the most accurate load.
A good example that I have found is with my custom 30/06. Shooting the 178 grn AMax. I can get my desired velocity with powders as fast as 4895 all the way to as slow as H4831SC.
however, the load with the 4831SC , which is 61.3 grns, is actually a compressed load. It is also the most accurate.

In my 6PPC competition rifles, the go to powder is N133. By all accounts, it is actually on the slow side for a 68 grn. The loads many of us shoot can only be used when we use a long small hole drop tube to get it all in there and still have room for the bullet.
I have found that this “compressed” load is by far the best combination for optimum Agging capability.

The same can be said for my 30BR. The load of either H4198 or LT-30 can also be classed as a 100%density load.

Of curse, there are multitudes of combinations where this simply is not true. Every bullet/power/barrel combo is different.

As for listed burn rate, myself and two friends found a stark discrepancy in the latest chart. That being, H1000 and N170.

We we’re working with the 7mm Geramo, which is a 6.5x55 necked up to 7mm and then Ackley Improved.

We found H1000 to be very accurate with 162 grn ELD’s. We wanted to try something just a little faster because the H1000 was a compressed load.

Ed got some N170. We dropped the load a couple of grns, but to our surprise, the velocity was wwwaaayyy down. We finally ended up with just about a full case, and the velocity was still an average 200 fps slower than the H1000.
TIf you look at that chart, you will see it listed before H1000.
By weight and volume in a given case, that simply is not true. By a long shot, (pun intended).