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.