Home Forums Hunting & Shooting Ask The Gunwriters Powder Burn Rate

Being an old loony, I have used IMR powders for 50 years but the new to me powders like 4166,8133,4451,4166 8208XBR 4955,7977, US869, etc have me lost as to burn rate. Is there a burn rate chart out like the old ones listed in the reloading manuals. I have newer Barnes, Nosler, Speer, Hornady and Lyman manuals but none list the burn rate like the old Sierra ones. None of the local gs have manuals and when I find powder with the above numbers I have no idea what it is for. Is there an IMR manual out there I'm unaware of?
Thanks, Mike

Just got the 2022 Hodgdon Annual magazine with a Midsouth order. They distribute IMR powder now. There is some data for the newer stuff in the more popular calibers in the style of the older IMR booklets. A relative burn rate chart is on p72.

Try this

www.hodgdonreloading.com/reloading-data-center

Ok, stupid question time....I'm tired so be gentle....

With a burn rate chart how does one apply it to the various calibers being reloaded?

Say I am loading 25-284.. how do I know what burn rates apply to it?

I’m thinking 25-06. But I'm sure MD will reply.

Maybe bad example.
I guess my question is actually how does one know what burn rate is applicable to any given cartridge?

Thanks, just what I was looking for.

It mostly boils down to expansion ratio, the volume of the case vs. the volume of the barrel.

In practice, just look at the powders that work in your cartridge. Powders with similar burn rates will typically have satisfactory characteristics for that cartridge, though you cannot estimate loads from burn rate.

300Savagehunter,

The method I use most, rather than depending on a burn-rate chart, is looking up the data for your cartridge and seeing which powders produce the most velocity with various powders and bullet weights.

This is pretty easy to do these days, since all powder companies provide FREE data on their Internet sites. And obviously you're on the Internet!

While the fastest velocities don't always mean the powder is ideal, it's a general indicator of what might work best.

Look at published data and observe which powder gives the highest velocity with your bullet weight, with safe pressures. Though all published data should be safe.

They are relative burn rates, not exact. You can use them to get a starting point. When substituting a powder my rule of thumb has been to start with the starting load of the next faster powder which I have data for and work up from there. Haven't blown anything up yet.....

And that's a good method.

When I've had to work with new powders or new/old cartridges where there isn't much (if any) pressure-tested data out there, I've often used the same method--or something similar like rate-charts. Then I work up to about the same velocity as similar powders produce.

Did this when the .300 WSM appeared, and there was almost NO handloading data, for an article that appeared in HANDLOADER back then, because the then-editor wanted to beat other magazines with published data. Within the next year, of course, pressure-tested data appeared from several sources--but the loads I published were all within a grain with the same bullet-weights, and many within a half-grain, and sometimes the exact same charge.

I started hand loading over 20 years ago, and with in a year did overload work ups of thousands of round on many powders and many bullets in 9mm, and similarly but to a lesser extent in 40sw, 10mm, 380, 32acp, 25 acp, 38sp, 357mag, and 45 colt, 223, 243, 7mmRM, etc. I have had hundreds of primers fall out.

AA#5 may be slower than Power Pistol on public burn rate charts, but not in reality at super high pressure.

Einstein may have been wrong when he invoked hidden variables on quantum mechanics, but I am not wrong about the hidden pressure variable in burn rate charts.

Exactly!

Just the difference between single-based and double-based powders results in varying results.

No to question your opinion , JB, but I would add best Velocity with a good load density. Right close to 100 percent but not compressed usually results in good loads....

Generally the highest velocity also comes from high load density.

However, I have also found that compressed loads often result in excellent results. This sometimes means pretty heavily compressed--but not enough for the powder to force the bullet forward in the case--which is one reason some handloaders experience higher pressures with compressed loads, especially with extruded powders.

One example is the load I've often suggested of 65-66 grains of Big Game with 286-grain bullets in the 9.3x62 Mauser cartridge. Have fired handloads over a decade old with that load, and they still result in the same velocity in my CZ 550, around 2475 fps. But when I broke one old round down, found the powder had clumped somewhat.

In fact, many benchrest shooters find the finest accuracy with compressed loads, because there's less velocity variation. This is also true with my own 6mm PPC bench rifle. But they also tend to use bullets touching or actually slightly seated into the lands. Which is, again, where I've found the best accuracy in my rifle.

I've used compressed loads successfully for decades and actually prefer them.
I have no idea why some are afraid to use compressed loads

Neither do I.

Have had the pressure-lab guys at two major powder companies flatly state that compressed loads generally result in more consistent velocities, which means the potential for finer accuracy.