Thread: 284 Winchester load data using AR2209

Originally Posted by Boomdog

Please see link to ADI load data it lists 57 grains as max load for AR2209 with 139g bullet

Data – Rifle – ADI World Class Powders and Ammunition

Also what changed with AR2209 from old to new?

Greetings @Boomdog,
A little after 2,000 AR2209 became a faster powder. There is some difference between lots or production batches but this change was more than that. I was working with the 129 grain SST in my 6.5x55 and bought a new container of AR2209 about 2,019. The first tests showed much higher velocities with the new powder than I was expecting so I went back and ran some paired trials using the ADI/ Hodgdons max of 45.5 grains with the following results.

45.5 grains AR2209 packed 2,001 2,720 fps. This is in line with the current ADI/ Hodgdons data of 2,703 fps at 45,500 CUP
45.5 grains AR2209 packed 2,019 2,805 fps.

I also went back to my old chronograph records and found that the older powder was still giving the same velocity back to when it was new. A search on the web found mention in this increase in speed for AR2209/ H4350 around 2,002 so the change in speed is real. With this increase in speed comes an increase in pressure which calculates to around 49,300 CUP, still within the 52,000 CUP which is a common max for new rifles and cartridges. 46 grains of AR2209 produced 2,855 fps with a calculated pressure of 51,200 cup but I have gone with 45.5 grains. I also ran some tests with the 120 grain with the same general results.

Looking at the Hodgdons/ ADI data it is clear to me that the 57 grain load is clearly an outlier and should not be used. Cross checking with data for the .280 Rem AI, which has a larger case shows this quite clearly and I am always suspicious of data with pressure in CUP.

All this likely sounds confusing to someone who I suspect may be at an early stage of a handloading career but using the most recent data available for the components you are using is essential to keeping out of trouble. To me working up a load with a chronograph is an essential to keeping out of trouble. Relying on "pressure signs" whatever they are will not. I see that you are in Christchurch so you may wish to go along to the Handloaders club at McLean's Island. They will have all the Kit and a mountain of knowledge to go with it.
Regards Grandpamac.