Please have a look at this burn rate chart.

The chart is continuously updated as I get feedback from reloaders who feel that a particular powder is more than three lines out of place. I received e-mail from a reloader who found that AR2209 and VihtaVouri N150 were not anywhere near equivalent. He says that N150 is much faster than AA2209. Does anyone have an opinion on whether AA2209 should be moved down the chart or whether N150 should move up? If N150 moves up, what about N550?

Comments on this, as well as any other powders on the chart, would be welcome.

Here's how I have them listed, if that makes any difference:

Faster
*170 N-150
171 S-361
172 AA-2700
173 W-760
*174 AR-2209
175 R-904
176 IMR-4350
177 H-4350
178 S-365
179 TU-7000
*180 N-550
Slower

It's a fine chart.....this is the first I've seen it.

Is it possible for two powders to have different specific gravity and the same burn rate?

I'm curious what the precise definition of "burn rate" is. How is it tested?

Steve,
Looking at the email I mentioned above, as well as your listing, it looks like I should move N150 up three lines, N160 up two lines, N550 down two and N560 down one?

vapodog,
Good question on how it is tested. I compiled the chart by comparing load data from the various manufacturers. The difficulty with placing some of the powders is that, in some calibers, their positions are reversed from other calibers, when comparing two or three. Any change of a position in the chart invariably has a ripple effect as well. I do not think one can actually place all the powders precisely to a particular line. The safe view would be to accept that any powder could be one line up or down.

Anyway, if we continue to fine tune the thing, it will become more accurate and a more useful tool for all to use. Thanks to all who have given input thus far.

Comparable burn rate charts are difficult, at best, due to most powders performing slightly differently in different size cases. But here are some observations that might help:

1. HS-7 and WW571 are the same spec powder, thus should be on the same line.

2. Lil Gun is definately faster than RL-7, so they should obviously be on different lines.

3. RL-7 is very close to IMR 4198, so it should not be two lines faster (as evidenced by it being inappropriatley placed with Lil Gun).

4. I agree that H-335 is typically faster than BL-C2, but not "two lines" faster. Also, BL-C2 and WW 748 (and WC-846) are all the same spec powder, so the two commercials should be on the same line.

5. IMR 4895 is so similar to IMR-4064 that there is sometimes equivocation about their relative speeds, so is should not be listed as two lines faster.

6. WW 760 and H-414 are normally the "same line" as the 4350 (which can obviously vary).

7. My trials years ago with H-870 and H-570 (not shown) indicated them to be virtually equal in speed, and either was no faster than H-5010, so, absent other evidence, that reconciliation needs to be made.

You might want to include the WC- line of surplus military powders: WC 844 = H335; WC 846 = BLC2; WC 854 = no telling what, as there are at least two highly different lots bouncing around out there that bear no relationship to one another; and WC 860 and WC 872, which are very close in burning rate in the two lots I've compared, are significantly slower than H-870 or H-5010 to which they are sometimes compared.

Hope this reduces, rather than increases, the confusion.

Gerard, I have looked at many Powder Burn Rate charts and have never found one that mirrors my reloading experiences (40yrs). Perhaps that is the reality of lot to lot variation.

Based on my testing, in the Winchester column, I would re-arrange WMR, WXR, & W785 to WXR, W785, and WMR. Apart from numerous loads fired in different rifles and calibres, I have also tested these powders with the same bullet weight in the same rifle on the same day, and found that WXR is about 0.5 to 1.0 grain faster burning than W785, and WMR is about 2 - 3 grains slower burning than W785. (Also, one of the Sierra Technicians alerted me to WMR being slower than as usually listed, and suggested I try it)

I note that you have the discontinued ADI AR2213 on the same line as H4831 extruded. I found that AR 2213 is about the same or about 0.5 grain slower burning than IMR 4831, and in an 06 sized case is about 2 to 2.5 grains faster burning than H4831. Using H4831 data for AR2213 would be potentially dangerous, and many gunwriters in Oz also mentioned this.

AR2213 was discontinued by ADI, when AR2213sc was introduced, but they are not the same powder or have similar burning rates.

I note that you have AR2217, H1000, IMR 7828, N165, on the same line. Although AR2217 and H1000 are the same powder, I and a few others in Oz have found that recent lots of AR2217 are about 2-3 grains faster burning than the H1000 lots produced by ADI.

I have found that in 06 sized cases, IMR 7828 is about 0.5 grains slower than Re22, and about 1.0 grain faster burning than N165.

I note that you have not listed AR2225 in the ADI column. This is the same powder as HRetumbo.

I also believe that N170 is incorrectly positioned. In recent testing in a 25/06 AI with 115,125, 142, & 156 grain bullets, I found that it was about 3.0 grains slower burning than Re25, 1.0 grain slower than AR 2225, and about 4.0 grains faster than H870.

I would be happy to email to you my load and chronograph data to verify and expand on the
above suggestions. Good luck on the list. Brian.

As Gerard mentioned, this "burning rate" business is complicated by the fact that two different powders' relative positions can even reverse, depending on the cartidge the powder is used in, and even depending on the loading density in the exact same cartridge, and projectile weight as well.

A good example of this kind of problem occurs with WW760/H414, powders which are considered "identical" except for the little variations of the kind associated with different lots of the same powder. In calibers around .30 or somewhat smaller, these two powders appear pretty much identical. But when used in large bore, large-capacity cartridges, they seem to diverge enough to be considered different propellants!

Perhaps the burn rate rankings could be done by the powders specification, if there is such a number, and not by actual tests of specific lots?

I say this because then it's the manufacturers responsibility to make the powder to spec and not for the ranking chart to follow what happened yesterday.

The local shop here is disposing of all AA powders as they vary too much.