Powder Numbers

[statjunk]

Is there a system for reading the numbers on powder? Example, comparing IMR 3031 to IMR 4898 would you be able to tell which burns faster or the difference in the size or shape of the pellets?

What about powders like RL 22?

Thanks

Tom

[hunter5325]

type powder burn rate into google search




Brett

As you can see, there is little reason for the numbers. IMR somewhat goes up as burn rate goes down, but several cases where that doesn't hold true, same with hodgdon. Alliants numbers generally go up as burn rate goes down but only for stick. Problem comes in as you have extruded, sphereical and flake powder.

http://www.hodgdon.com/burn-rate.html

[statjunk]

Found a website called Reload Bench. It has a lot of good info. Wow a lot of the powders that I'm using are way at the bottom of the list of top 173 powders.

Thanks

Tom

[eldeguello]

ORIGINAL: statjunk

Is there a system for reading the numbers on powder? Example, comparing IMR 3031 to IMR 4898 would you be able to tell which burns faster or the difference in the size or shape of the pellets?

What about powders like RL 22?

Thanks

Tom

Well there's sort of a system, within the individual product lines of various makers, SOMETIMES!! For example, take IMR powders. IMR 3031 burns faster than IMR 4895. IMR 4320 is slower than IMR 4895,IMR 4350 is slower than IMR 4320, and IMR 4831 is slower still. IN the Alliant lineup, RE 7 is faster than RE 15, which is faster than RE 19, RE22 is even slower, etc. But there is no way to relate this to the numbers used by the other makers, except by accident!

In addition, the difference in quickness between powders of the same make are not uniform, either.

Take a look at these powder burn rate charts.

http://home.hiwaay.net/~stargate/powder/powder.htm
http://stevespages.com/powderrates.html

They show you where a given powder fits into the group, by relative quickness. But they cannot tell you EXACTLY HOW MUCH DIFFERENCE there is between powders on the list.

YOU MUST STILL SELECT A POWDER FOR A GIVEN USE FROM A PUBLISHED SET OF LOADING DATA. YOU CANNOT USE A POWDER BURN RATE CHART TO DETERMINE HOW MUCH OF A GIVEN POWDER YOU CAN USE BASED ON SUCH A CHART!! ALL THE CHART CAN DO FOR YOU IS SHOW YOU WHICHPOWDERS MIGHTDO WHAT YOU WANT TO ACCOMPLISH WITH A GIVEN CARTRIDGE & BULLET.

You choose the powder, then look for beginning load data for it.

[TJEN]

In adition any powders actual burn rate can differ depending on which case its in. Thats why actual reloading data from ballistions doing real world testing with each cartridge case. IE reloading manuals.

[falcon]